Date: Mon, 12 Oct 2009 01:23:25 -0700 From: "K. Macy" <kmacy@freebsd.org> To: Attila Nagy <bra@fsn.hu> Cc: freebsd-fs@FreeBSD.org, Pawel Jakub Dawidek <pjd@FreeBSD.org> Subject: Re: ARC size constantly shrinks, then ZFS slows down extremely Message-ID: <47C0A3F4-6431-49E5-B780-FA162946C288@freebsd.org> In-Reply-To: <4AD2E118.2050202@fsn.hu> References: <4AC1E540.9070001@fsn.hu> <4AC5B2C7.2000200@fsn.hu> <20091002184526.GA1660@garage.freebsd.pl> <4ACDA5EA.2010600@fsn.hu> <4ACDDED0.2070707@fsn.hu> <20091008160718.GB2134@garage.freebsd.pl> <4AD2E118.2050202@fsn.hu>
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> > The amd64 machine started to loose ARC memory again. See these: > http://people.fsn.hu/~bra/freebsd/20091012-zfs-arcsize/zfs_mem- > week.png > http://people.fsn.hu/~bra/freebsd/20091012-zfs-arcsize/memory-week.png > > Your patch was active between 7 and 9. You can see that the ARC size > was somewhat constant. > On october 9, I installed Kip's modification, and ARC size started > to decrease. > BTW, previously (before october 7) I set the arc min size to 10-15GB > (can't remember the exact value), but now it runs with the defaults > (only the max size is set): > vfs.zfs.arc_min: 3623878656 > vfs.zfs.arc_max: 28991029248 > > As you can see, there are plenty of memory. This machine uses UFS as > well (and writes it heavily), maybe that's what affects ZFS size, by > caching a lot of stuff? > Currently, the inactive page queue will grow until ARC is shrunk to arc_min. I think I'll probably spend some time making the ARC play better with the page cache this week. Unfortunately, under heavy memory pressure when competing with UFS the ARC will degrade to LRU, but I think that is still an improvement over the current static sizing with low and high water marks. -Kip
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