{"action":"created","issue":{"url":"https://api.github.com/repos/pagespeed/ngx_pagespeed/issues/904","labels_url":"https://api.github.com/repos/pagespeed/ngx_pagespeed/issues/904/labels{/name}","comments_url":"https://api.github.com/repos/pagespeed/ngx_pagespeed/issues/904/comments","events_url":"https://api.github.com/repos/pagespeed/ngx_pagespeed/issues/904/events","html_url":"https://github.com/pagespeed/ngx_pagespeed/issues/904","id":57145280,"number":904,"title":"pagespeed MemcachedServers  \"host1:port1,host2:port2,host3:port3\";","user":{"login":"vincentami","id":3817765,"avatar_url":"https://avatars.githubusercontent.com/u/3817765?v=3","gravatar_id":"","url":"https://api.github.com/users/vincentami","html_url":"https://github.com/vincentami","followers_url":"https://api.github.com/users/vincentami/followers","following_url":"https://api.github.com/users/vincentami/following{/other_user}","gists_url":"https://api.github.com/users/vincentami/gists{/gist_id}","starred_url":"https://api.github.com/users/vincentami/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/vincentami/subscriptions","organizations_url":"https://api.github.com/users/vincentami/orgs","repos_url":"https://api.github.com/users/vincentami/repos","events_url":"https://api.github.com/users/vincentami/events{/privacy}","received_events_url":"https://api.github.com/users/vincentami/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-02-10T08:39:53Z","updated_at":"2015-02-10T13:36:32Z","closed_at":null,"body":"\"This allows PageSpeed to batch multiple Get requests into a single MultiGet request to memcached, which improves performance and reduces network round trips.\"\r\n\r\nHI ALL ,  if i add more memcache server here,  the performance of \"multipe Get\" is always better than Get ? What do you think about the \"Facebook's Memcached Multiget Hole\" ? If i make consistent hashing loadbalance at the front server and only left one memcached server for each ngx_pagespeed server, wheather the performance improved or even worse?  \r\n\r\n\r\n\r\n"},"comment":{"url":"https://api.github.com/repos/pagespeed/ngx_pagespeed/issues/comments/73699587","html_url":"https://github.com/pagespeed/ngx_pagespeed/issues/904#issuecomment-73699587","issue_url":"https://api.github.com/repos/pagespeed/ngx_pagespeed/issues/904","id":73699587,"user":{"login":"jeffkaufman","id":262566,"avatar_url":"https://avatars.githubusercontent.com/u/262566?v=3","gravatar_id":"","url":"https://api.github.com/users/jeffkaufman","html_url":"https://github.com/jeffkaufman","followers_url":"https://api.github.com/users/jeffkaufman/followers","following_url":"https://api.github.com/users/jeffkaufman/following{/other_user}","gists_url":"https://api.github.com/users/jeffkaufman/gists{/gist_id}","starred_url":"https://api.github.com/users/jeffkaufman/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jeffkaufman/subscriptions","organizations_url":"https://api.github.com/users/jeffkaufman/orgs","repos_url":"https://api.github.com/users/jeffkaufman/repos","events_url":"https://api.github.com/users/jeffkaufman/events{/privacy}","received_events_url":"https://api.github.com/users/jeffkaufman/received_events","type":"User","site_admin":false},"created_at":"2015-02-10T13:36:32Z","updated_at":"2015-02-10T13:36:32Z","body":"In general you want all your ngx_pagespeed servers in one location to share the same memcached server or set of memcached servers.  This is because optimized resources created in response to one request from one user will generally also be needed later by other users and on other pages.  Sharing your cache across all the servers means less wasteful re-optimization.\r\n\r\nAs for how many memcached servers, I would start with one, run for a while, and look at the eviction rate.  Generally you want low evictions, and high evictions often means your cache is too small and you should add another memcached server.  (Though high evictions can also be a symptom of other problems, such as accidentally generating a cachebuster url server-side on your resources.)"}}