{"comment":{"url":"https://api.github.com/repos/Brainfood-com/lizardfs/comments/11308054","html_url":"https://github.com/Brainfood-com/lizardfs/commit/44851769216155336d06d045d858fc03d5084472#commitcomment-11308054","id":11308054,"user":{"login":"schue","id":418424,"avatar_url":"https://avatars.githubusercontent.com/u/418424?v=3","gravatar_id":"","url":"https://api.github.com/users/schue","html_url":"https://github.com/schue","followers_url":"https://api.github.com/users/schue/followers","following_url":"https://api.github.com/users/schue/following{/other_user}","gists_url":"https://api.github.com/users/schue/gists{/gist_id}","starred_url":"https://api.github.com/users/schue/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/schue/subscriptions","organizations_url":"https://api.github.com/users/schue/orgs","repos_url":"https://api.github.com/users/schue/repos","events_url":"https://api.github.com/users/schue/events{/privacy}","received_events_url":"https://api.github.com/users/schue/received_events","type":"User","site_admin":false},"position":null,"line":null,"path":"","commit_id":"44851769216155336d06d045d858fc03d5084472","created_at":"2015-05-21T15:06:48Z","updated_at":"2015-05-21T15:06:48Z","body":"Perhaps but short circuiting to the local inode also seems like a mistake. We are attempting to build a grid where each node is both a unit in the distributed storage system and a host for computation. With multicore systems this seems like a common configuration. The prefer-local feature greatly distorts the dynamics of the grid's behavior based on VM placement, which is essentially random. Also, in the case of a heavily utilized parallelized VM focusing reads which would otherwise be spread across the entire network onto a single host has catastrophic effects on seeks. On magnetic media the reads which would otherwise be distributed across all the spindles of the grid now attempt to service from the small set of drives on the local box. Wait times explode, not only for the VM but for any other system attempting to read chunks from that host. With SSDs the problem would probably be much less pronounced but with magnetic media it is truly awful. You should try building a test harness and watch it for yourself. It will become clear how destructive this attempted optimization can be to performance."}}