Le 14/10/2014 18:17, Gregory Farnum a écrit : > On Monday, October 13, 2014, Lionel Bouton <lionel+c...@bouton.name > <mailto:lionel%2bc...@bouton.name>> wrote: > > [...] > > What could explain such long startup times? Is the OSD init doing > a lot > of random disk accesses? Is it dependant on the volume of data or the > history of the OSD (fragmentation?)? Maybe Btrfs on 3.12.21 has known > performance problems or suboptimal autodefrag (on 3.17.0 with 1/3 the > data and a similar history of disk accesses we have 1/10 the init time > when the disks are in both cases idle)? > > > Something like this is my guess; we've historically seen btrfs > performance rapidly degrade under our workloads. And I imagine that > your single-disk OSDs are only seeing 100 or so PGs each?
Yes. > You could perhaps turn up OSD and FileStore debugging on one of your > big nodes and one of the little ones and do a restart and compare the > syscall wait times between them to check. > -Greg > Will do (have to lookup doc first). Thanks for the suggestions. Lionel
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