On Fri, May 1, 2009 at 4:12 PM, Louis Kowolowski <lou...@cryptomonkeys.org> wrote: > On May 1, 2009, at 1:53 PM, Pete French wrote: >> ... >> The tuning isn't there to improve performance, it's there to prevent >> the box going titus due to a panic when the ARC gets too big, and >> you are missing the mian one, which is to limit the size of the ARC. >> On recent versions of BSD (and you are running 7.2, so thats fine) then >> the defaults for kmem size are fine, but you still need something like >> this: >> >> vfs.zfs.arc_max="256M" >> >> In there to stop the ARC growing. thats the only tuning I have on >> my 4 gig machine, which takes a steady stream of data and is used >> for taking backup snapshots. ZFS is excellent, and for me is perfectly >> stable, to the point where I am starting to roll it out to production >> machines, with the above tuning. >> > I agree, although I'm using 384 instead of 256. My systems have been > running in production for almost a year now w/o any ZFS issues.
The exact value to use will depend on the system. Particularly on the amount of RAM in the system, and what kmem_max is set to. A "rule-of-thumb" we've been using is: kmem_max should be half of the amount of RAM (or 1.5 GB as that's the current max) arc_max should be half of kmem_max Using those, we've been able to run our ZFS boxes without any kmem panics, even when doing rsync backups for 102 remote servers every night to a single box. Finding those values was fun. :( -- Freddie Cash fjwc...@gmail.com _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
