vm.kmem_size_max/vm.kmem_size_min define the range vm.kmem_size can be set to. vm_kmem_size specifies the actual kmem size.
ARC size in turn limited by vm.kmem_size. If you want to bump ARC size, you do need to bump vm.kmem_size. --Artem On Fri, Feb 12, 2010 at 11:36 AM, Steve Polyack <[email protected]> wrote: > On 02/12/10 13:47, Artem Belevich wrote: >> >> On Fri, Feb 12, 2010 at 10:31 AM, Steve Polyack<[email protected]> >> wrote: >> >> >>> >>> Has anyone had an issue with the ZFS ARC max being limited below what has >>> been defined in /boot/loader.conf? I just upgraded the RAM in a >>> ZFS-equipped system and attempted to devote 4GB to the ARC cache by >>> placing >>> the following in loader.conf: >>> vfs.zfs.arc_max="4096M" >>> >>> However, after rebooting, querying the sysctl gives me this: >>> $ sysctl vfs.zfs.arc_max >>> vfs.zfs.arc_max: 1726489600 >>> >>> or about 1.7GB, an odd number that I can't find any references to. For >>> reference, I'm running 8-STABLE (as of Jan 19th) on an amd64 system with >>> 8GB >>> of RAM. The system was previously very stable with 4GB of RAM and a >>> 512MB >>> arc_max. I have not modified vm.kmem_size_max (defaults to ~330GB on >>> amd64) >>> or any other ZFS tunables. I'd also like to avoid syncing up to the >>> current >>> 8-STABLE if at all possible. >>> >>> Thanks, >>> Steve Polyack >>> >>> _______________________________________________ >>> [email protected] mailing list >>> http://lists.freebsd.org/mailman/listinfo/freebsd-stable >>> To unsubscribe, send any mail to "[email protected]" >>> >>> >> >> Check your vm.kmem_size. Default setting is way too low. Set it to at >> least double of desired arc size. >> >> --Artem > > I mentioned it briefly, but vm.kmem_size_max was left at the default for > amd64. At 330GB it is way above and beyond what will ever be allocated to > ARC: > $ sysctl vm.kmem_size_max > vm.kmem_size_max: 329853485875 > > > _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "[email protected]"
