Date: Mon, 29 Sep 2008 10:13:28 +0200 From: Bartosz Stec <admin@kkip.pl> To: Ben Kelly <bkelly@vadev.org>, freebsd-stable@freebsd.org Subject: Re: vm.kmem_size settings doesn't affect loader? Message-ID: <48E08E28.90009@kkip.pl> In-Reply-To: <C0588997-E405-4651-8D4A-205B8163F97A@vadev.org> References: <48DB6772.1060400@kkip.pl> <20080925130227.GA13497@icarus.home.lan> <48DB9CAA.9060807@kkip.pl> <20080925145154.GA15486@icarus.home.lan> <48DCA0AF.5050000@kkip.pl> <C0588997-E405-4651-8D4A-205B8163F97A@vadev.org>
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Ben Kelly wrote: > On Sep 26, 2008, at 4:43 AM, Bartosz Stec wrote: >> Jeremy Chadwick wrote: >>> >>> These are the tuning settings I use: >>> >>> vm.kmem_size="1536M" >>> vm.kmem_size_max="1536M" >>> vfs.zfs.arc_min="16M" >>> vfs.zfs.arc_max="64M" >>> >> Yesterday I've added 512 MB memory to box (sum 1,5GB), and set >> vm.kmem_size and vm.kmem_size to "1024M". With pieces of 1024MB, >> 512MB, 256MB, 256MB available and 3 memory slots it is hard to have >> 2GB RAM ;) >> Until now it survived world cleaning/building/installing/bonnie++ >> benchmarkink/fs scrubing and general usage. Memory usage seems >> stable. If unfortunately kmem exhaustion will happen again I will >> experiment with ARC settings. >> IMHO you've explained gently a lot of zfs tuning concerns in this >> thread and they should be added to tuning guide - espacially >> explanation of ARC and prefetch settings. Thanks again! > > Did you increase KVA_PAGES in your kernel config as well? > > The default of 256 only allows 1GB of kernel memory total. Setting > KVA_PAGES to 384 would probably be good for a kmem_size of 1GB. This > would give leave you with 512MB of space for other things in the > kernel. In your kernel config: > > options KVA_PAGES=384 > > Sorry if you already knew this. I know its in the zfs tuning guide. > I just hadn't seen it mentioned in the thread yet and wanted to make > sure it wasn't missed. > > Hope that helps. > > - Ben > Indeed I know that. options KVA_PAGES=512 is included in my kernel config. Until now: # uptime 10:12 up 3 days, 10:32, 1 user, load averages: 0,00 0,03 0,00 Thanks :) -- Bartosz Stec
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