Date: Mon, 7 Mar 2011 11:37:16 +0100 From: Kai Gallasch <gallasch@free.de> To: =?iso-8859-1?Q?Micka=EBl_Can=E9vet?= <canevet@embl.fr> Cc: freebsd-fs@freebsd.org Subject: Re: kmem_map too small with ZFS and 8.2-RELEASE Message-ID: <3E910C24-FA7E-461B-9677-ED551D69FBF2@free.de> In-Reply-To: <1299226985.3391.18.camel@pc286.embl.fr>
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Am 04.03.2011 um 09:23 schrieb Mickaël Canévet: > Hello, > > I know there is a lot of threads about "kmem_map too small" problems on > former versions of FreeBSD with ZFS, but on the wiki > (http://wiki.freebsd.org/ZFSTuningGuide) it is said that "FreeBSD 7.2+ > has improved kernel memory allocation strategy and no tuning may be > necessary on systems with more than 2 GB of RAM." > > I have a 64bits machine with 16GB of RAM with FreeBSD 8.2-RELEASE and no > tuning: > > # sysctl -a | grep -e "vm.kmem_size_max:" -e "vm.kmem_size:" -e > "vfs.zfs.arc_max:" > vm.kmem_size_max: 329853485875 > vm.kmem_size: 16624558080 > vfs.zfs.arc_max: 15550816256 > > This morning this server crashed with: > > panic: kmem_malloc(1048576): kmem_map too small: 8658309120 total > allocated Hi, Mickaël. If you want to "get a picture" on how setting ZFS tunables in loader.conf affect the different cache sizes and cache hit ratios, I can recommend installing the freebsd port sysutils/munin-node together with sysutils/zfs-stats and the following munin ZFS plugins: http://exchange.munin-monitoring.org/plugins/search?keyword=FreeBSD Regards, Kai.home | help
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