Date: Wed, 7 Apr 2010 23:25:57 -0400 From: Rich <rincebrain@gmail.com> To: Adam Nowacki <nowak@xpam.de> Cc: freebsd-fs@freebsd.org Subject: Re: ZFS arc sizing (maybe related to kern/145229) Message-ID: <i2l5da0588e1004072025w953351c1l8400fbd0c1766c5f@mail.gmail.com> In-Reply-To: <4BBD15E7.5010006@xpam.de> References: <z2o5a1151761004071105kb129ca4q7dfd002270d53561@mail.gmail.com> <h2u5da0588e1004071146lf09ef89eo217933f75ec7a88b@mail.gmail.com> <4BBD15E7.5010006@xpam.de>
next in thread | previous in thread | raw e-mail | index | archive | help
kstat.zfs.misc.arcstats.memory_throttle_count: 673016 Since UFS has no files of any reasonable size on it (it's literally just rootFS)... - Rich On Wed, Apr 7, 2010 at 7:31 PM, Adam Nowacki <nowak@xpam.de> wrote: > check kstat.zfs.misc.arcstats.memory_throttle_count > This counter is increased every time zfs thinks system is running low on > memory and will force a write flush and reduce arc size to minimum. Biggest > problem is that the code is counting only free memory and completely > ignoring other memory that can be immediately freed like cached files from > ufs. This is very easy to trigger on mixed ufs and zfs system by just > reading enough data from ufs to fill its cache, zfs will begin throttling > and will continue doing so even with no further ufs reads or writes. > > Rich wrote: >> >> A datapoint for you: >> Now running 8-STABLE (plus the mbuf leak fix which went in recently), >> here's my ARC stats and ARC sysctl settings after the server was up >> for about a week (5 days) after that: >> ARC Size: >> Current Size: 587.49M (arcsize) >> Target Size: (Adaptive) 587.63M (c) >> Min Size (Hard Limit): 512.00M (arc_min) >> Max Size (Hard Limit): 3072.00M (arc_max) >> >> ARC Size Breakdown: >> Recently Used Cache Size: 98.28% 577.50M (p) >> Frequently Used Cache Size: 1.72% 10.12M (c-p) >> >> ARC Efficiency: >> Cache Access Total: 2602789964 >> Cache Hit Ratio: 96.11% 2501461882 >> Cache Miss Ratio: 3.89% 101328082 >> Actual Hit Ratio: 87.65% 2281380527 >> >> and >> >> vfs.zfs.arc_meta_limit=1073741824 >> vfs.zfs.arc_meta_used=548265792 >> vfs.zfs.arc_min=536870912 >> vfs.zfs.arc_max=3221225472 >> >> So it very clearly limits to near the minimum size, but whether this >> is design or accidental behavior, I'm unsure. >> _______________________________________________ >> freebsd-fs@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-fs >> To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" >> >> > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?i2l5da0588e1004072025w953351c1l8400fbd0c1766c5f>