Date: Sat, 7 Apr 2007 20:03:19 +0200 From: Bernd Walter <ticso@cicely12.cicely.de> To: "Florian C. Smeets" <flo@kasimir.com> Cc: freebsd-fs@FreeBSD.org, freebsd-current@FreeBSD.org, Pawel Jakub Dawidek <pjd@FreeBSD.org>, ticso@cicely.de Subject: Re: ZFS committed to the FreeBSD base. Message-ID: <20070407180319.GH8831@cicely12.cicely.de> In-Reply-To: <20070407165759.GG8831@cicely12.cicely.de> References: <20070406025700.GB98545@garage.freebsd.pl> <20070407025644.GC8831@cicely12.cicely.de> <20070407131353.GE63916@garage.freebsd.pl> <4617A3A6.60804@kasimir.com> <20070407165759.GG8831@cicely12.cicely.de>
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On Sat, Apr 07, 2007 at 06:58:00PM +0200, Bernd Walter wrote: > On Sat, Apr 07, 2007 at 03:59:02PM +0200, Florian C. Smeets wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > Pawel Jakub Dawidek wrote: > > > On Sat, Apr 07, 2007 at 04:56:45AM +0200, Bernd Walter wrote: > > >> My sandbox just has 128MB RAM so kmem was set to ~40M. > > >> After raising kmem to 80M it survived copying the file, but paniced > > >> again while tar -xvzf the file into the same pool. > > >> vfs.zfs.vdev.cache.size is unchanged at 10M. > > > > > > 128MB RAM of suggested minimum in ZFS requirements, but it may be not > > > enough... Minimum of ARC is set to 1/8 of all memory or 64MB (whichever > > > is more). Could you locate these lines in > > > sys/contrib/opensolaris/uts/common/fs/zfs/arc.c file: > > > > > > /* set min cache to 1/32 of all memory, or 64MB, whichever is more */ > > > arc_c_min = MAX(arc_c / 4, 64<<20); > > > > > > Change 64 to eg. 32, recompile and retest? > > > > > > > Hi Pawel, > > > > i had the same problems like Bernd while trying to copy the src tree to > > a ZFS volume. I have 384MB RAM but i got the same "kmem_map: too small" > > panic. I compiled my kernel like you proposed and now i am able to copy > > anything to the volume without panic :-) > > I had increased RAM to 384 and still had a panic with default kmem > (IIRC around 100M) and even increasing kmem to 160M did help a long > time, but still produced the panic after a while. > I don't think 64M applies here as the real limit. Now with 240M kmem it looks good, but I'm still unshure: kstat.zfs.misc.arcstats.c_min: 67108864 kstat.zfs.misc.arcstats.c_max: 188743680 kstat.zfs.misc.arcstats.size: 87653376 c_max seemed to be increasing with kmem, but I did compare it with a remebered value. Should be good with: vm.kmem_size: 251658240 But top shows wired memory which is roughly twice the size of arcstats.size, so I'm still worried about kmem exhaustion if ARC runs up to c_max. Since the c_min/c_max values also influence the available RAM for other purposes as well, can we have it at least a loader.conf tuneable? Otherwise - the reboot after the panics where impressive. No long fsck times or noticed data corruption - even with NFS clients. All in all it is a great job. -- B.Walter http://www.bwct.de http://www.fizon.de bernd@bwct.de info@bwct.de support@fizon.de
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