Date: Thu, 30 Jul 2015 15:37:58 +0300 From: Lev Serebryakov <lev@FreeBSD.org> To: Steven Hartland <killing@multiplay.co.uk> Cc: freebsd-fs@freebsd.org Subject: Re: ZFS on 10-STABLE r281159: programs, accessing ZFS pauses for minutes in state [*kmem arena] Message-ID: <843537366.20150730153758@serebryakov.spb.ru> In-Reply-To: <55BA0F41.6070508@multiplay.co.uk> References: <164833736.20150730143008@serebryakov.spb.ru> <55BA0F41.6070508@multiplay.co.uk>
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Hello Steven, Thursday, July 30, 2015, 2:49:21 PM, you wrote: > You don't need to do that as record set size is a min not a max, if you > don't force it large files will still be stored efficiently. Oh, I thought it is max after reading some blog-posts and forum threads (this one, for example: https://forums.freebsd.org/threads/1mb-recordsize-performance-recordsize-discussion.50414/ and this one https://blogs.oracle.com/roch/entry/tuning_zfs_recordsize and this https://www.joyent.com/blog/bruning-questions-zfs-record-size) Does it mean, that files could not occupy less than 128K with default setting? Anyway, I'll recreate pool. >> It looks FreeBSD contains bug about year ago which leads to this behavior, >> but mailing lists says, that it was fixed in r272221, 10 months ago. > When this happens what is the state of memory on the machine? Now I'm in single-user mode and have some problems to analyze massive output of "vmstat -z" :) top shows 4.5-5G of total ARC size and very low (~150Mb) free memory. > Top will give a good overview, while sysctl vm.stats.vm and vmstat -z > will provide some detail. > If you're seeing significant memory pressure, which could well be the > case with a mixed ZFS UFS system during this transfer (they use Now I have pure ZFS situation, with ZFS to ZFS transfer. Mixed scenario with UFS to ZFS transfer didn't show this behavior. > competing memory resource pools) then you could try limiting ARC via > vfs.zfs.arc_max I'll try to set it ot 3G... > You could also see if the patch on > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=187594 help. I should try this, but for now I should migrate as quickly as possible & return my spare HDDs which are lent to me for short time... -- Best regards, Lev mailto:lev@FreeBSD.org
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