Good evening everybody. Welcome to the Private Property Farming Podcast. My name is Mbali Mawka and thank you so much for joining us this evening. I just want to say that before we go into our guests this evening, I just want to give you an update that please, this is a live show so our guests are joining us live and so you can ask us questions, please comment as you always do. But without further ado, I'm joined by two ladies today which is quite exciting, you know, it's a table of women and it's always great to get women in the agricultural space. And today we are joined by Marty Konradie as well as Marsha LaRue who's coming back the second time on the podcast and Marty is the medical advisor at Agility Agri and Marsha is the sales executive at Agility Agri. Ladies, thank you so much for joining us. Welcome to the podcast. Thank you. Thank you. I know Marsha we've had you on the show before but just maybe to start again just by your introduction and what is it that you do for Agility Agri and then Marty as well you can tell us about your position and your role within Agility Agri. Thanks and Bali and it is such a pleasure to be back with you and the audience and I'm sure we're going to have such a fantastic discussion leading up to the first one that we've had and I mean it's a pending topic as always. So just as a reintroduction, I am Marsha LaRue. I'm the sales executive at Agility Agri and my main purpose definitely and especially for this audience is to assist our audience should it be from an individual or a group perspective with the right decisions to make when it comes to health care and especially what we're talking about today, employee well-being. Awesome. Marty? Yes, so I'm the medical advisor at Agility Agri. So what I do is kind of more behind the scenes and we try to make sure that we develop a product that really looks after the employee's health. So to make sure that all the elements are there and then also for all of the other health products that Agility manages just the medical advisory. Oh wow, awesome and Marty I'm sure your role right now is quite overwhelming because like we're saying just before we started the podcast that you know a lot of people are getting sick they're having the flu and they're testing negative for COVID and it seems like everybody's not getting sick with you know unexplained illnesses or you know the typical illnesses that we would usually get during this time around not specifically COVID because the minute a person coughs everybody thinks it's COVID so you must be busy this time around.  Awesome so for anyone watching the podcast tonight and maybe just might think they do have an understanding of what employee wellness programs are but maybe just unpack it to us in terms from an Agility Agri perspective what are first and foremost employee wellness programs? So employee wellness programs is actually a combined program that consists a little bit about health promotion so that is you know when an employer makes a point of promoting health you know wash your hand posters or that type of just health promotion and how important it is to wear your PPE or all of that. Then there's also the component of well-being and more the wellness offerings so when you have your wellness days or when you do a HIV testing campaign or a mental health program and that type of more evaluating the people and ascertaining you know their health and then there is the last component which is more employee assistance programs so that also offers so much more to an employee where you can really assist him so once you've identified a program you can actually offer him whether it is helplines so what Agility offers is we've got the nurse helpline which just answers a little bit of clinical questions you might have or a financial helpline because often we underestimate the effect that financial problems could have on your mental well-being and even your physical well-being and then there's also the legal helplines which is just offering that a little bit of extra advice you might not know you need and you know there's always the mental type of support that you can get through what is often referred to as a psychosocial helpline and then some companies also offer some rehabilitation if they do identify that maybe a lot of employees are struggling with alcohol dependency or that type of situation so the combined you know when you combine all of those products you kind of get to an employee wellness program as a whole. Wow and I want to bring in Marcia here into the conversation to ask basically because you are Agility Agri and you are focusing on a specific niche or segment in the market which is that being Agri how different is the employee wellness programs that Agility offers Agility Agri offers to its client as opposed to normal employee wellness programs. Well I think the key here is you know the uniqueness of our members and then obviously especially the Agri industry so one gets quite a lot of options out in the market to identify what you as an employer would like to do in terms of an employee well-being program be it as Dr Marty said a financial aspect legal aspect a health aspect or maybe risk management from an employer perspective for their return on investment so what makes Agility Agri different in this market is the way and the methodology we take and put together in order to create the right solution when it comes to employee well-being we spoke previously about locations demographics you know farms are not always located near metropolitan areas so how does one provide a service to employees to better their own personal lifestyle and as an employee but being so far removed from the city life so that's where the absolute focus comes in to say all right these are the providers in that location that we can access employee well-being from an agility perspective for instance we have one of our products actually complementary to any employer group that belongs to Agility and also our medical aid health grid which we administrate so that means we can already give one aspect a tick and I hate the word ticking a box because it's it's more than that you know HR lots of times have this onus on them to say but you know what we have to look after employees what what can we do all right we've put this in place but does it actually is it being utilized how can we measure the outcome of this benefit that you are giving as an employer so from Agility's perspective for our employer groups and especially on the farms we have a helpline a 24-7 helpline which these employees can access for either health financial or legal assistance which is fantastic because this is you know and things never happen in working hours especially when it comes to health it is late at night something happens to my child and I'm not sure how to respond to that and it's just that quick call to a professional to say this is the situation what is your advice so it's become very very very crucial and nearly like gold for our employers at the moment because the employees feel a sense of duty that's coming from the employer to take care of them and giving them an access to a professional that is not linked to the organization you know we we proud and as South Africans we have a sense of culture that we don't always want to let people know our weakness or when we are actually experiencing something difficult like a financial or legal situation and especially with COVID you so scared you just wipe your nose or sneeze because the individuals around you might think that you've got COVID and you can then as a stigma think that you could lose your job so this is an absolute channel that is private it is absolutely free and the employee doesn't have to worry about the advice that they're getting and that it will be shared somewhere else that could potentially be threatening to them. Wow thank you. Marty I want to know at what point do companies feel that they need an employee wellness day like what are the signs that they should pick maybe they should look out for to say that okay maybe we should start organizing an employee wellness day so what at what point do companies implement or start to introduce employee wellness days? So yes employee wellness days it's not the it's not the solution to everything but it is a very good starting point so it actually shouldn't be triggered by anything it will be best if it is just done before there are any problems you know that is the ideal and that is what is often offered if you go to an external company like Agility to bring in people and arrange a day before there are any triggers and you know what then can happen is from that day you can determine the need for either future wellness days or so but your unfortunately reality is that often first the people become a bit sick regular sick leave also one of the signs that companies have to look out for is when they know that the stress levels are high of employees and mental well-being in the workplace is becoming a very you know major topic in the industry of occupational health so often in wellness days we thought okay high blood pressure testing then you know cholesterol check weight check a little bit of lifestyle advice that used to be a wellness day nowadays a wellness day is a little bit more specialized and you know mental health services or education or just supportive people that is becoming a little bit more important and creating awareness also of workplaces of what the stress levels is so yeah we hope to change and get more wellness days out there you spoke about productivity so does this mean that make basically you know for farm managers or farm owners or just anyone in management if they start also you mentioned obviously that we shouldn't wait for triggers right but just for a productivity perspective anybody in management even if when should when they start seeing signs of their team underperforming and it's not necessary any has anything to do with their physical strength or you know how fast they could do stuff in the farm but just basically when people start noticing that ah this certain or this team is really not mentally at work you know they're physically at work but they're not mentally at work maybe they're not communicating properly with their team members they're just forgetting small tasks are those also maybe it's just some of the signs to say okay I think the team is in a downed need you know and I mean we are in a global pandemic a lot of people are being affected by a number of things and so could it be that even when we spot these type of signs is it safe to say that a wellness day is due? Definitely so I mean those are the starting signs of burnout it definitely indicates stress levels in your employees and the problem is one employee who is very stressed or anxious for whatever reason will affect the others around them and so it is you know it is not just a single employee who might need help it is probably of the whole group of the employees so those are definitely signs to watch out for you know decreased productivity and all of that but like I also just mentioned wellness days it is a good trigger to you know then arrange a wellness day but then to also make sure that the wellness day focus on the specific problems and it's also at that point where you can immediately start with a little bit of health education to the people or just enabling them to deal with the issue even before on a wellness day is arranged so you know just telling your employees about help lines that's available you know there are employee wellness companies who offer these services but there are also free help lines you know out there so just educating your employees in that situation and then also arranging a wellness day is definitely good. Great and this question goes to both of you ladies and especially I'm sure Marsha because Marsha because you're the one that engages directly with the with the clients so basically how does agility every implement these wellness programs on farms and basically what really happens in the wellness day because like you said Marti it's not really checking blood pressure you know or you know the weight and this and the height of the person anymore it goes into much deeper level than that does it maybe also involve just is it like people just sitting around a circle and talking about the problems like therapy firstly how are they implemented and what yeah just basically give us a scenario of how you conduct the wellness day. It's a very good question and it's like Marti says you know it's it's not the england be all but it can definitely mitigate quite a lot of risk factors that's been identified so typically with a scenario with a group for instance what we do is we keep a reporting mechanism which is a risk management tool that we use in terms of claim histories for the group so for instance if we identify that there's been an influx on specific doctor visits or claims for specific medication so this will always be a generic overview never from an individual perspective but one gets a very good idea what the trend would be in the company and what the staff are going through so for one instance that I'm dealing with now and actually a wellness day an employee well-being program that I'm initiating at one of my employer groups was we saw a massive massive trend for on the claims history of these employees that were on the medical skin for diabetes and eventually realized that the environment that these individuals work on and and the type of diets that they are following weren't very healthy which obviously immediately flagged a risk for for diabetes hypertension so immediately identifying those triggers one can then say let's do a wellness day where we can have these tests done a fingerprint test let's check your glucose let's check your cholesterol let's look at your BMI and while the nurses are at this wellness day they will then advise these individuals based on the test results what is a better step to take so again and I always mention it but I'm very passionate about the duty of care of an employer so the employer is actually now bringing a professional to the workplace such as a wellness day where these individuals can get these simple tests done that can prevent something bigger happening and leading the warning and listening to the test results putting measures in place then to say well how can we take this wellness day further now again we're not taking a box we want to make sure that the well-being of these staff are actually being measured being managed and then saying such as Dr Marty to give some dietary advice what are good tips that these individuals can follow how can HR get involved with it so that's one scenario so you can pick up trends from the the risk management reports that we do for our employers they would also sometimes feel that they would like to run a specific campaign for a day or for a month with the employees and these are all customizable so really really depending on what is the need what is the trend that's showing and what is that little risk that's popping its head out that we'd like to get under control and I mean with that obviously putting this in place you've got a healthy employee group and a happy employee group absolutely Marty is that is there anything you want to add there no I completely agree um happy workforce is a productive workforce um so it used to be neglected previously you know wellness wasn't one of the top priorities um often in mining it was legislated so it was just done tick but it wasn't really you know followed but nowadays there's so much you can do and you can offer like Marsha said you know to the people um that you can really make a difference like I said happy employee happy workforce talking about that happy or positive outcomes what have been some of the positive outcomes that you've experienced out of the the wellness days from my side and my experience definitely employees that feel that they are being taken care of first of all everybody loves you know a you know a occasion where a provider comes through to them looking after them and contributing to their own personal health so it definitely creates a sense of morale um height and positivity um and doing these tests and giving the results and having a backup plan um lessens absenteeism so it really becomes a fantastic way that doesn't always have to be expensive even if it's just sharing information like where we are now and what we spoke before about flu what do I do um should I always go for a test should I what are the the trends that we have to look at and just getting a professional to come speak to the employees so it definitely creates a lot more information and education so that people can make more informed decisions and then for the employer definitely lessen absenteeism and more productivity because people are now informed and they know what to do with triggers that they normally not would have known about do you have any uh uh uh things to share about some sort of positive changes that have come out of world day wellness days over and above what Marcia said well one thing that I could add you know she she definitely touched the most important points there but and one thing that I could add is maybe um many companies are rurally located and the employees do not always have access to um I want to say reliable healthcare or trustworthy sources um maybe not even to google uh you know we turn to it very quickly but wellness days and then employee wellness programs create this opportunity to enable your workforce who might not otherwise have access to these sources to then take responsibility for their own health and I think that is what um employee wellness programs can really do. Wow I just want to say to anybody watching at home please uh if you've got any questions for um Marti or Marcia tonight please drop them into the comment section and we're happy to answer any questions that you may have uh around employee well-being around wellness days basically on our discussion and if you're just joining us we're joined by Marti and Marcia from Agility Agri discussing the importance of employee wellness days or employee wellness programs within the Agri sector and um so just to sum up our conversation Marti and Marcia I just want to know and especially just as a farmer as an entrepreneur um I mean we're faced under a lot of pressure just personally I think as a farmer farm as a farm owner and obviously as a business person farming is not the most easiest sector to be in and so there's a lot of pressure and demands just running the farm at the end of the day and just managing it as a business because you know under these tough economic climatic conditions um it's quite it can get quite stressful for business owners or farm owners to say but even going back to the employees as well still we are in a global pandemic a lot of communities are facing a lot of poverty pressures with service delivery etc and that could definitely affect the psyche and well-being of farm workers so what can we all do as people and professionals within the Agri sector to ensure the well-being of not only the farm workers farm owners but just ourselves and individuals and I forgot to say actually just not focusing on the farms it's also professionals like yourselves because you guys are servicing the Agri industry and if your clients Marti I'm sure you made it might attest to this if your clients are stressed in essence you will also be stressed because you know that you know you're servicing a clientele that's quite stressed that's got extreme pressures and demands from all forces so what can we all do as individuals as professionals in the Agri sector to ensure that not only our physical health but also mental health is taken care of especially in such tough economic times so I'll start at that Marti I will have lots to add probably so um obviously um your own wellness and healthy lifestyle and um your mental health that is important so if you aren't healthy you can't help other people you can't help your family um and you actually make a more negative environment at work so you know we all know the healthy habits you know more exercise and more vegetables add a little bit of vitamins there lots of water um so preferably not smoking less alcohol so those are the harder ones um but uh following a healthy lifestyle will be um very good for you and then I think how we support other people is to be understanding um and to be aware of other people's problems you don't have to be the one to fix it but you could know someone or something that could help them um and being supportive and understanding will create this environment where people might um to promote help seeking behavior so just having the service of maybe a nursing call or a psychosocial helpline um and promoting the use of that will actually help um all the people around you so you know that's from my side I can definitely add to that and say um and what Dr Marti said um and what I've realized um within my own position and role as you said and Bali is support support and understanding having empathy that people are dealing with quite a lot of pressure that we normally wouldn't have dealt with all together in one basket so having empathy having understanding and realizing as an individual that you're not alone in feeling how you are feeling and if there are a psychological aspects coming up which is very prevalent at the moment um if you look at the statistics of individual suffering from depression now and having mental illness and especially those that already suffered from mental illness the escalation that it's gone to now um within the pandemic that we've been in but also the other stresses that come um it's it's that old saying don't judge until you've walked in that person's shoes and I think more than ever now we need to be aware of it that we are all dealing with some sort of stress and um being empathetic listening understanding and having a little bit more patience can definitely help um something that's perceived as a negative to actually be explained as what the reality is and then going on to that looking after ourselves physically can definitely help increase our energy levels so you know obviously it goes hand in hand if you eat well you've got more energy if you've got energy you feel more positive so trying to always remind yourself that at the end of the day it is still you fighting the battle with everybody around you and the more we look off to ourselves the more we will be able to also look off to others from a psychological and a physical perspective wow thank you must say I mean you know as you're talking it it definitely hit home because um sometimes a shy away from reading the news because of the terrible things that we read especially the farming sector if it's not farm work um farm murders this week it's hearing about a farmer who committed suicide because you know uh maybe they they they farm just couldn't recover from drought etc and you know they're under financial stress um yeah so I think and it's it's topics that we really don't really um uh deeply dive into and really unpack and you're right it can definitely get lonely especially in the farming sector um over and above just having a a business in general so I think what's so assuring to know farm agility agrees that there is a support line most importantly a 24 hour support line so you know members can obviously get that support to say if I'm feeling depressed or if I'm having anxiety and I'm sure it could be happening amongst woman farmers or woman farm workers with all the farm work uh farm murders etc uh you know in the violence that is happening so it's great to hear that you're not only providing a service where you know we're just paying a monthly fee and then we just you know uh contacting agility agree if we're sick or if we're not feeling well or if you want to design uh or come up with uh wellness days but you are there from uh you know just a call away to support um just on any other things that are just triggering uh the low productivity but ladies it's been fantastic speaking to you guys today you know you're just unraveling a lot of more things that we still need to do as a sector being a community still supporting each other still and really attacking or tackling issues that are really important not only from a workspace but just making sure that we are all safe we are all you know mentally fit to still come at work to be productive to take care of ourselves and just our working environment so thank you firstly for the work that agility agrees during the sector and thank you guys for for your roles and your participation in the podcast today you definitely did educate me more on what your service offering provides not only to farm owner myself but more importantly to to to the workforce it's been an absolute pleasure Bali and know that we are there and always happy to to chat to you and the audience with anything else that that that you would like us to to unravel and support you with thank you thank you so much Marty any last words no no all the best on the farms um there's always challenges but I hope you all stay very healthy so awesome thank you so much we've just come to the end of the show this evening and I was joined by Marcia and Marty from Agility Agri if you missed tonight's conversation please head on to our Facebook and our YouTube channel where you'll find this video posted and we didn't get any comments today I think maybe you're just listening quite intently with all the things we've been unpacking but I hope that the show today has been very educated and informative most importantly to you and anybody you know that is working within the agri sector and I think what I'd like to leave you with lastly is that you know if you're feeling down if your mental health is just not improving and you're just noticing a common trend where nothing is making you happy definitely speak to someone even if it's not Agility Agri or if you're not a member definitely speak to someone closest to you and if you need further support and especially for people working in the Agri community I think Agility Agri is a company that maybe you could reach out to you whether it's Marcia or Marty this evening but we'll put their link to their website on our show notes on YouTube and I hope this was quite an eye-opener of the many many challenges that we face in farming over and above the positive stories that we always love to share but thank you so much for tuning in and I wish you a very very good night and I will see you next week Tuesday at 8 o'clock thank you


Hello. Thanks for listening. My name is Alberto Garcia. I work for Igalia on the QMU project. In this presentation, I'm going to talk about the work that I have been doing lately. This is related to the QCAD 2 file format. As you know, this is the native file format just by QMU and it supports many features as encryption, compression, backing files, etc. But the questions that I'm going to try to answer today is, why is it that sometimes this is slower than a raw file? There's many reasons for that. It can be because it hasn't been configured correctly, we're not using the right options for our setup. Of course, it can be that the driver can be improved, there's still room for improvement there. Three years ago in the KVM for 2017, I was talking about these things, so you can check the talk, it's in YouTube, it's available. Today I want to focus on the problems that are a result of the very design of the QCAD 2 file format. Let's start with the format itself, how it works. The basic idea of the QCAD 2 file is to divide it into clusters of the same size, 64K by default, but it can be changed when the file is created, from 512 bytes to up to 2 megabytes. There are different cluster size, I'm not going to go into the details now, but let's focus on the data cluster, which contains the data that the guest can see. So every time the guest needs to read data, it goes to the QCAD 2 file. If the cluster has been allocated there, then it just reads the data for the cluster. But if the cluster has been allocated, then it contains zeros. Or if there's a backend file, it goes to the backend file and checks the data is there. So the cluster is the smallest unit of allocation. So every time we allocate a new cluster, if the right request is smaller than the cluster size, then we need to fill the rest with data. And the data means we either go to the backend file and get it from there. So in the case of this image that you see, we will write to the area in pink, we will need to go to the backend file and read the areas in dark blue and copy them to the active file. Or if there's no backend file, we just fill it with zeros, but we still need to fill it. So the problem is that, of course, QMU needs to perform additional IO to copy the rest of the data. So the copy and write can be an expensive operation. As you can imagine, when we increase the cluster size, we have to do more copy and write so the performance goes down. You can see that in the table. I had to mention though that if you don't have a backend file, then as I said, we should fill the cluster with zeros, but QMU nowadays uses F allocated to try to fill it in a more efficient way. So if that works, the file system supports it and the operating system supports it. This is very fast and then the cluster size doesn't have any effect. But if that doesn't work, then it goes to the slow path of writing actual zeros to this and then you can see the numbers that I'm showing in the table. If there's a backend file, however, there's no alternative. We need to go to the backend file and get the data from there. So that's where the cluster has an effect. The other consequence of this is of course the larger the cluster size, we do more IO, we do more copy and write and then the image is bigger. You write the same data, but you get a bigger image in result because you are duplicating data from the backend file. How much? Well, this depends a lot on the use case. There are reports that can be 30% larger or 40% larger, but it depends a lot on the use case. I was just doing a couple of tests for this presentation and you can see that if we have an empty image and we write 100 megabyte worth of random 4K requests, the impact of having a larger cluster size is very big. If we go to the default 64K, we get a 1.6 gigabyte image, which is more than 10 times what we were trying to write, which is a lot. But if we go to the maximum cluster size, we get 29 gigabytes, which is 300 times the initial, the amount of data that we want to write, which is very big. Of course, this is an extreme case. Normally, in a real-world scenario, we don't just write random write requests. But it gives an idea of what the problem is. Then I did a second test. I took an empty one terabyte image and I created a file system there. You can see the file system itself, the metadata used by the file system, which is just 1.1 gigabyte. But if you increase the cluster size and you take it to the maximum, then you use one more gigabyte. Just creating a file system, an empty file system with nothing else in it. So in summary, if we increase the cluster size, we get less performance because there's additional IO that needs to be done. And we also get larger images and duplicate data. So if things clear, then we don't just reduce the cluster size. The problem is that it's not so easy because smaller clusters means more metadata and more clusters also. So what does this mean? Apart from the guest data itself, Qco2 images also need to store metadata about the cluster. So important things are the cluster mappings, which map the guest addresses to the host addresses, and reference counts. All clusters in Qco2 have reference counts, so we're going to see later. So if we're going to have more clusters, we're going to have more of them. So it means more metadata. So the mapping from the guest clusters to the guest offsets to the host offsets is done using this structure that we call L1 and L2 tables. This is a simple structure that maps virtual offsets into host offsets. You can see an example here in this graphic. The L1 table is just one per image, per snapshot actually because Qco2 format is one per snapshot, so we're not going to go into that now. But the table itself is very small. It's for a one terabyte image, just 16K, so there's nothing. It's stored continuously in the image file. And QM always keeps it in memory because it's very small, so there's no problem with that. And basically, the table just contains pointers to the L2 tables. The L2 tables, there can be many of them. Initially there's none, but they were allocated in demand as the image grows. The L2 tables are always one clustering size, never more, never less. And they also contain basically good pointers to the data clusters, plus additional information that we're going to see later. The thing is that, of course, if we reduce the cluster size, then we need more entries. So graphically we'll have two clusters and we make the clusters twice as small. Then we're going to have four clusters and we'll have three this time. So half the cluster size twice the metadata. That's the basic idea. Here we see on the table what's the maximum metadata for a one terabyte image. As you see, if you reduce the cluster size by half, you increase metadata by two, which is a very big difference, of course. So choosing the right cluster size has a very big impact on the amount of metadata that you have in the image. So what does this mean? Every time we need to do an IO request in the guest, QMU needs to go to the L2 table and get the host offset. It needs to transform the guest offset into the host offset. So that's one additional IO operation per request. And this has a very big impact on performance. So what QMU does in order to minimize it is it keeps the L2 tables in memory. There's a queue code to cache, the L2 cache for that purpose. I was talking about it in more detail in the previous presentation that I mentioned earlier. And it has a very big impact. If we increase the cluster size, we get much more performance. So in this example that you see here, the maximum cache needs is 5 megabytes, and we get 40,000 operations per second. But we reduce the cluster size, the cache size, sorry, that the performance goes down very quickly because it means that we need to go to the disk to get the L2 metadata more often. So reducing the cluster size means we have much more metadata and we have much more RAM that we need to keep that metadata in memory. Then there's the reference counts. Every cluster in the queue code to the image has a reference count. All types of clusters, not just data clusters. These are used, for example, for snapshots because you need to know who is using each one of the clusters. And they are stored in a two-level structure and it's very similar to the L2 tables that we just described. So of course, allocating new clusters has an issue on overhead because you need to update the reference counts. So with more clusters, we need to allocate more of them. In general, we have a lot of small clusters. We need to allocate first more clusters. We need to allocate more L2 tables. We need to allocate more reference blocks. And all that together means that although normally reducing the cluster size increases the performance because there's less copy and write involved, once we go under a certain limit and this example is less than 16k, the performance goes down very quickly. As you can see, the performance when we have 4k clusters is horrible. Even though with 4k clusters there is no copy and write. But we have to allocate so many clusters, so many L2 tables, so many reference blocks that the performance is very bad. So the situation so far is that we cannot have two big clusters because they waste too much space and there's additional IO needed for a copy and write. And we cannot have two small clusters because they increase the amount of metadata and if we decrease it too much then it's also a very bad performance. And this is the consequence of the format itself. It's not something that you can fix in the driver. So what can we do about it? So the solution that I'm describing in this presentation is called a subcluster allocation. The basic idea is that we have big clusters in order to reduce the amount of metadata but each one of them is divided into subclusters that can be allocated separately. So we have faster allocations and less disk usage. So graphically, a normal L2 table looks like this. We have two data clusters as you can see. With subclusters, each one of the data clusters is divided into 32 subclusters of the same size. They are allocated separately. So in this case, only the errors in blue are actually allocated and used in the space in disk. Internally, the L2 table contains, as I said earlier, pointers to the data clusters. Basically, it looks like this. It's the cluster offset plus a few more bits that indicate whether the cluster is allocated or not. It's compressed or not, or it contains zeros. Contained zeros is a feature from QCAL2 that means that the cluster doesn't have any other data than zeros, so there's no need to go to the data cluster and read from there. We just know that it's zeros, and we can return zeros without doing the IO. So if we have subclusters, we need to store additional information for that. There's no space here. So we added this extended L2 entries, which is basically very similar to the ones that we had before. But they contain an additional bitmap indicating the status of each subcluster. So with this, it's one of the individuals that can be allocated, unallocated, or can be all zeros also. Compressed clusters don't have this, however. Compressed clusters cannot be divided into subclusters, and anyway, compressed clusters doesn't really make so much sense to use compression with extended L2 entries because they are different use cases. So the use cases that I see for subcluster aggregation are two. One of them is having very large clusters because we want to minimize the amount of metadata and the amount of memory that we need, but still want to have good IO and have smaller images. And the other use cases that we want to maximize the performance. So we want to keep the location unit as close as possible to the guest block size. So we want to minimize the amount of copy and write and get the maximum performance. So what does this mean? If we make the subcluster size equal to the request size, that means the file system block size, then there's no copy and write at all and we get the maximum performance. We can see here that compared to the default setup without subclusters, in some cases, we get 10 times more IO operation per second. And if we go to the cases where the subcluster is 4K or less, which is the size of the request in this example, then we get the maximum performance, which is 12-13K IO operation per second. Without the backing file, the relative differences are the same. Of course, it is faster because we don't need to go to the backing file to read the data. And again, I want to mention that if the file system supports emptying the cluster with FL-O-K, then this is going to be much faster than this and then actually using subclusters doesn't really make a difference. It's not going to be faster with that. So you have to consider that. About the space, of course, if we have now the smaller allocation units, then the images grow much less. So we compared the random writes that I mentioned before. We write 100 megabytes in 4K write requests. The end result is much, much smaller, as you can see in the example. So of course this improves a lot the... how we use the disk. And although extend the L2 entries are twice as large as normal L2 entries, in principle it would use more metadata. However, since it's one of the L2 entries, now points to 32 subclusters, the end result is that we have 16 times less metadata for the same unit of allocation. So we compare units of allocation, clusters in traditional L2 entries and subclusters in extended L2 entries. We see that for a 64K cluster size we would need 128 megabytes of cache for a one-terabyte image. But with extended L2 entries, if we have 64K subclusters, we only need 8 megabytes, which is much less. So we can have much larger clusters and keep good performance without needing so much memory for the cache. So things that need to be taken into account. All this looks good, but this is not magic, so... This feature is useful during allocation. Once the cluster is allocated, there's no QCAL2 works just fine, with or without subclusters and you get good performance. So once the image is allocated, this is not going to really help so much more. Again, with compressed images it doesn't make sense. I think it's a completely different use case. So this is not going to give you any benefit. You're going to have twice as much metadata and you're not going to see any benefit. And if your image doesn't have any backing file, maybe you don't see any speedup. As I said, QMU tries first to use FAllocate to allocate clusters efficiently. So you have to try that first to see if it helps in your scenario. But if you're using backing files, it's not going to help in any case. And then, of course, images created with this extended L2 entries are not going to be possible. You're not going to be able to read them with older versions of QMU. And I don't expect that this feature can be backported easily, so you will need the latest versions of QMU. So how do I try this? This is not available in QMU yet. It's not in any release. It will probably be available in QMU 5.2, but the feature is complete and it's already in the repository. You can test it already. So you just download the latest version from QIT. You compile it and you create an image with the option extended L2 enabled. And that's all. You also probably want to have a larger cluster size. The default cluster size is 64K, but with this feature it makes sense to use larger clusters, so be sure to try those. But that's all that you need to do. Again, feedback, back-reports, et cetera are very much appreciated. This feature is complete, but it's new, so any testing, anything that you try, suggestions, et cetera, we will be happy to hear about that. You can write to the mailing list or you can contact me directly. And that's basically it. I would also like to take the opportunity to thank OutScale, which is the company that is sponsoring all my work in QMU and in this feature in particular. So everything that you are seeing here today is all. I hope that you enjoyed the presentation and I'm open to any questions. Thank you.


The speakers, Lene Husten-Massen is sitting over there. She's not speaking today, she's just observing. But it's director of museum Scannabar and a partner in the Eastgate Project. Lene Mollerwald is a museum inspector at them. Abby, this is the case where we're gonna present from today and also museum Scannabar. And then Myana Poe, director of chosen, this is Scannabar. And I am Nina Vajpojicin, and I'm the product manager at the Eastgate Concept. Where we are, just where we talk from, is in Denmark, in the Lakeland, the biggest city here is almost just in the coastal capital. Perfect. Well, shortly, just wanna tell a little bit about Eastgate as a concept. It combines landscape storytelling with world history in terms of fine modern art. And has existed since 2014 and done several projects. And in each project, we always have the same elements. But on different sites, we always have excavations or places where they've been excavated. We have art in situ and we have audience and visitors with tourism perspective. And also in all projects, we work with the process, one big event, and then the event is always temporary. And then we work more permanently developing or in people's mindset. And the case we're gonna talk about today is rebuilding the Abbey Eastgate 2017. And also just shortly, if you could just now comment on the ideologies taking things away from the site and putting it in boxes. The main thing for Eastgate is to bring the story back to the sites because we're always site specific. So with art and people involvement, bring the story back to the site and give them the story. The site is a monastic ruin. It was excavated in the 1930s and the 1970s. As you can see on this slide, there's hardly anything, or there's a little bit of a comment left, but there's not a lot above ground. And we're actually walking around in the ruin park as an archaeological excavation. What we know, it would have been like, is very monumental because we have a system on the street where the building is preserved. Today, the house, the site house, opened at ruin park and museum. This is twice six to seven thousand half year because we're only open half year. The purpose of making this event was to create an image of, and also to create an essential awareness of the site because we are in the process of developing the attraction. As you can see here, this is a cardboard installation that we were presented by the artist, Olivia Prussett. And then the next slide. We had an event six days in May last year in consistent of workshops and the event where we built the cardboard monastery together and also the demolition of cardboard and eminence. We had to take out the erection and the eminence and it was supposed to stand for 24 hours. 250 people helped creating the cardboard in four days before the event.  We didn't know how many people would turn up. We got the message up. Internet would be local, all the local channels. We expected somewhere between 500 and 5,000 people to come in because we were all long on help from volunteers, we couldn't build this ourselves. So it was a community project. We're just gonna show a small movie from the last left. It weights over 1.6 tons. So you had to lift approximately 20 kilos per person or something. So it was only doable, people staying and helping. So it's just a short movie. And really really scary as well. It's not finished yet. They're still in process of putting things in. So I guess you can almost feel in your stomachs. This was really a moment in time, unforgettable, not only for us, but for the four and a half thousand people that were there. At that time, as Nina said, the sculpture weighed more than a ton and a part of that was three and a half kilometers of gravity. Just imagine, what we all experienced was that at that time, co-creation really meant something. It may be a buzzword, but this is co-creation. We had lots of volunteers working with the installation. As Nina said, it was a week before, so we had lots of different volunteers, the old, the tired people. But what we found out, what we saw, was that there was a form of volunteers, volunteers that we almost knew, the school kids and the good friends of the monastery. But the audience here also spontaneously became volunteers. When it stood there, at the end of the day, I guess at least a thousand people had touched the cardboard boxes, for when they arrived, planned out, during the workshops, racing it, and when it finally collapsed. What you saw when it collapsed was that the audience, especially the young ones, the very young ones, would run up to the installation and jump in it. We relied on that because we needed to re-sign the cardboard. So we had to make a plan of again. And I have one picture of people like Ann's carrying them in a row, all these cardboard boxes to the right re-signal thing. So co-creation became for real, real time. We also gained what was the purpose of the awareness and attention. We, speaking about external branding, it really worked. We were out on all the platforms and channels and national TV. So there was a lot of fuss about the monastery, the museum, and the area. Internally, there was branding in the sense of, for example, pride. I think everyone that touched the cardboard boxes at the end were very proud. So what we also gained was a lot of new owners. We saw that the old ownerships were refreshed by this event, but we also had great new and broader ownership. So more ambassadors, more attention, more external and internal branding, all leading up to that the monastery and museum is now undergoing a great development plan which has just been decided. So now we're looking forward to the monastery shining even more and the whole area through the monastery shining. And that is because of the volunteers, the locals, all the new ambassadors involved in this conflict. Thank you very much. Yes? What did you say? Oh, okay. Thank you very much.


Now I want to move over to some more advanced topics. We are really going to look at what happens as time goes to infinity. Now that's a very important concept in the life sciences. Depending on what we are dealing with, say for instance we are dealing with some disease and epidemic, that might last for months or years. And in that setting, infinity for us might mean what happens over one or two years. Not nearly infinity mean an infinite number of time. We really can't fathom that. But many times we just want to muddle things at infinity. So that's a very important topic. We'll also look at continuity. When is a function continuous? And that has a lot to do with limits. Have a look at some of these advanced topics. We'll make them quite easy. We know so much about limits now. And we know that we can write an equation. It can help us to see what will happen in the future as the limit as t approaches infinity for instance. But it has proper mathematical uses as well. Imagine we model something and we want to see what the rate of change is. And we all know the rate of change is the first derivative for instance. The first derivative with respect to time in our instance. But you can only take the derivative on a certain domain if a function is continuous in that domain. If it's not continuous in that domain, you can have problems relying on taking a derivative in a certain section. Now that is one of the other beauties of a limit. It really helps us to tell if a function or a graph is continuous at a certain point. So when can we have discontinuities? Well, there's a few examples there. What if I have an f and a that is not defined? So I have this function f. It's modeling something for me, but at a certain point t, or a, I should say, where t equals a, it is not defined. What about the natural log of t? Well, that's an extreme example here. But the natural log is not defined when t is less than or equal to zero. So there's definitely a discontinuity at time equals zero for instance. It's never going to be defined there. So what about when a fiber function in t and t equals a is defined, but that limit does not exist? For instance, if my model requires a piecewise defined function and the limit as t approaches the f of t simply doesn't exist. Or for instance, the left and right end limits are not equal. That would mean that there's a discontinuity in my graph there. Other problems I can think of as vertical asymptotes. For instance, when the f of t equals the tangent of t, there are no various vertical asymptotes. And certainly there is discontinuity of the function and you cannot take the derivative in areas where there is a discontinuity. So certainly limits help us as far as that is concerned. Now certain discontinuities are removable. At the left top here, I have the f of t equals t squared plus 2t minus 15 over t equals 3. What happens? Imagine that models some growth of some bacteria for me over time. Just imagine that. What happens at time equals 3? Well, if I plug 3t equals 3 into my equation, then I'm going to get zero over zero. That doesn't work. There's certainly a hole in my graph at that spot. It turns out to be at 3.8. We'll see now why that is. But there's certainly a discontinuity there. There's ways to get rid of it. I can do the limit as t approaches 3 from the left side and the right side. And if I plug in values closer and closer and closer to 3 from both the left and the right side, I'm going to get to 8. There's certainly a limit exists there. And if I wanted to do this limit properly, I can make use of something that we'll definitely look at a bit later. At the indeterminate forms. Forget that for now. Let's just see one way we can remove discontinuities mathematically. I can certainly factorize the numerator into t minus 3 and t plus 5. The t minus 3's cancel and I'm going to have to t plus 5. So the f of t of t squared plus 2t minus 15 over t minus 3 is just the same as writing the f of t as t plus 5. And if I plug in 3 now, I get 8. I don't get 0 over 0. Be very careful now. Even though I can simplify t squared plus 2t minus 15 divided by t minus 3, even though I can simplify that as t plus 5, those two are not the same thing.  I've removed that, but you can clearly see although they are algebraically equal, they are not the same function. So if I were to model something, I would have to do this piecewise to find function to remove that discontinuity properly. Not by simplification, but by rewriting my original f of t as such, when t is not equal to 3, I can have the t squared plus 2t minus 15 over t minus 3. But when t equals 3, I have the fact that the f of t equals 8 or t plus 5. That has removed the discontinuity for me. What about non-demovable discontinuities? If you have the f of t equals 1 over t squared, there's no way to remove that. There's nothing I can do to remove that. You can clearly see from the left and the right-hand side, it goes up to infinity. In other words, the limit does not exist at t equals 0. If that limit does not exist, it means there's a discontinuity in my graph. It doesn't just hop over from left side of 0 to the right side of there. That limit does not exist, therefore there is a definite discontinuity in my function f of t equals 1 over t squared. I can generalize that 1 over t squared is the following. f of t equals some constant a. In my example at the top, that was 1, and it didn't even be t squared. It just can be t minus b to the power n. A and b are just members of the set of real functions. As long as n is more than 0, we're going to get the same kind of vertical asymptote at b. At the top it was t minus 0, squared b was 0, hence my vertical asymptote being at b. Now let's look at another non-removable discontinuity, and that's infinite oscillation. You can zoom in on the cosine of 1 over t, closer and closer to 0. It just starts moving up and down even more. It goes absolutely crazy. It never settles on a solution, a certain y value. That is certainly a non-removable discontinuity. It's one that you'll come across often. Put it in your memory banks. The cosine of 1 over t as t approaches 0 does not exist. You can clearly see that that's a beautiful graph actually, and you're never going to get a solution there. There's a non-removable discontinuity, and certainly in the domain on either side of 0, you really can't take a derivative there. You have a discontinuity. Now one that we're going to come across very often. I'm going to include it in this lecture because you're going to use it so many times. Not of 1 over t, but 1 over t squared, but 1 over t. What happens to the limit as t approaches infinity of 1 over t? You can clearly see the graph there. You can clearly see we're going to approach 0. Plugging in values, large and larger values for t there, you see we are just going to get closer and closer to 0. Again, I can generalize this to say that the limit as t approaches plus or minus infinity of some constant a, which is a member of the element of the set of real values, divided by t to the power k. For k larger than 0, you can't have t to the power negative 2. It's got to be larger than 0. The power there and t of k must be defined. t of k can't be 0, or the natural log of something that's less than 0. It's got to be defined, obviously. All of those will equal 0. Anyway, I can write the limit as t approaches positive infinity of 3 million, divided by t to the power 6. It's going to be 0. Are we going to make use of that? Yeah. Again, you see there on the left-hand side, if I just plugged in infinity there, it's going to be infinity over infinity. Again, it's indeterminate form. We're going to deal with indeterminate form. Before we get there, there's another way to look at this. I've got t squared plus 2 over t to the power 3 plus 2t to the power 2 plus t minus 2. The limit as t approaches infinity of that. Now look at what I can do. Remember I said that the limit of t as t approaches plus or minus infinity of some constant over t to the power k, as long as k is equal 0 and t of k is t to the power k is defined equal 0. I can change that numerator and denominator, so I have quite a few examples of that. If I were to divide the numerator by the largest powered variable in the denominator, now look at the denominator, it's t cubed is the largest power. If I divide the numerator and the denominator by t cubed, I'm going to end up with all of those. Look at it. Plus I have to skip the step by making use of the limit laws. Remember if it's something like this, I can just take the limit individually in there. But look what has happened. If I were to divide t squared plus 1 by t to the power 3, I'm left with 1 over t, and I know the limit of that as t approaches infinity is just 0. I'm also going to be left in the numerator with 1 over t cubed, that still fits the bill of a over t to the power k. And now in the numerator, in the denominator, I should say I have the limit of 1 because t cubed divided by t cubed is 1, and the limit of a constant is that constant. So suddenly I have a constant in the denominator. All the others are just examples of a over t to the power k in some form, and I know those limits will always be 0. In other words, I have 0 over 1, which is the 0. So again, that limit is going to approach 0 as t approaches infinity. It's going to be 0 as t approaches infinity. So there's some important limits to remember. The one we've just seen is t approaches positive and negative infinity of some constant over t to the power k. With the constraints that I said t to the power k must be defined, and k must be larger than 0, it's always going to be 0. The limit is t approaches 0 of a over t to the power k. So this is something else. Now that's the empty set. That is just going to blow up to infinity. So that will never work under those constraints, and that's why I put the open-closed little curly braces, meaning the empty set. Just another way to write that that limit does not exist. We've seen the trigonometric functions before. Remember that the limit is t approaches 0 of sine of t over t, or the sine of t, those are both 1. We've also seen that the limit is t approaches 0 of the cosine of 1 over t. Remember that's the one that just jiggles up and down, even more. Same happens for the sine of 1 over t. Again, that limit does not exist. Therefore I put the empty set there. Excellent.


Preveyors of erythritol like to talk about how this low-calorie sweetener is a natural constituent of foods like melons and peaches, but it's in such tiny amounts— the average person only gets like 25 milligrams— and now that it's manufactured commercially, intake could easily be a thousand times that. I've done a few videos about it. What's the update? Well, here's a paper with a twist. Erythritol, a non-nutritive sugar-alcohol sweetener and the main component of Truvia brand sweetener, is a palatable, ingested insecticide. Huh? Yeah, they found it. Killed fruit flies. And so they suggested we start using erythritol as a safe, sustainable approach for pest control. It evidently induces in flies lethal regurgitation. Also kills the yellow fever mosquito, termites, and ants. So why isn't erythritol sprayed on crops? Because it hurts the crops too, and the dose is needed to kill insects that has damaging effects on the plants. But hey, if it hurts plants, maybe we can use it as an herbicide too. Okay, but what about just as a human sweetener? We've long known that the bacteria that produce dental plaque on teeth aren't fueled by erythritol, and they can't seem to make acid out of it, either to cause cavities. As long as plaque stays above a pH of 5.7, food is safe for teeth, and swish with some erythritol, and nothing happens, whereas then swish with some table sugar, and pH dips down to the danger zone. But xylitol, a sugar outcrop similar to erythritol, isn't just dentally safe in terms of not causing cavities, but may actually have an active cavity-stopping benefit. See, dental cavities are reversible if detected and treated sufficiently early. Early on we thought that cavity reduction found in xylitol studies, where people chewed on xylitol gum or sucked on xylitol candies, may have just been due to indirect effects, like getting your saliva going. Or hey, every xylitol candy may be one less sugar candy, so maybe it's just a substitution effect. Can you imagine how you might design a study to test if there were direct xylitol effects? I'll give you a moment to pause, and try to come up with something. How about secretly randomizing people to use xylitol-containing toothpaste? And indeed, boom, a reduction in tooth decay compared to the control toothpaste without the xylitol. So xylitol really does seem to have cavity-reducing effects. What about erythritol then? All studies strongly support the idea of erythritol as being cavity-reducing, too, perhaps even more so than xylitol. For example, more than twice the drop in the amount of plaque after six months sucking on erythritol candies versus xylitol. In fact, that extends out at least three years. Yeah, but did that actually translate into fewer cavities? We have all these studies pointing in that direction, however no long-term human cavity trials on erythritol have been completed.  Significantly lower number of cavity-ridden teeth and surfaces were found in the erythritol group. Another advantage to erythritol is safety to dogs. Doses of xylitol, as little as a half teaspoon and a 30-pound dog, can be life-threatening, whereas erythritol is so well tolerated with no adverse effects reported upwards of, like, more than a cup a day, suggesting it could even be used as like an ingredient in chew toys or something.


When you strengthen liberal democracy, populism by definition becomes weaker. One of the most important ways to strengthen liberal democracy is to actually explain it. And sadly, I think quite a lot of our politicians don't fully understand what liberal democracy means and that it goes beyond popular sovereignty and majority rule.