[OpenIndiana-discuss] Mitigating the performance impact of scrub

Udo Grabowski (IMK) udo.grabowski at kit.edu
Thu Sep 27 15:54:54 UTC 2012

On 27/09/2012 17:44, Reginald Beardsley wrote:
>  From observed behavior, it appears that the scrub is consuming too large a share of DRAM (12 GB in this case).

in /etc/system: (then reboot)
set zfs:zfs_arc_max = 0x200000000  (=8 GB)

cuts it to roughly that value. Also, you can set zfs primarycache and
secondarycache properties to metadata or none to lower the cache
impacts (if workload is not affected too badly by this). On smaller
machines (~6-12 GB), we set "metadata" and arcsize to less than 1GB.
Scrub always hits you badly on smaller machines (weak IO), so we do
this regularily via a cronjob only on sundays.
Dr.Udo Grabowski    Inst.f.Meteorology a.Climate Research IMK-ASF-SAT
www-imk.fzk.de/asf/sat/grabowski/ www.imk-asf.kit.edu/english/sat.php
KIT - Karlsruhe Institute of Technology            http://www.kit.edu
Postfach 3640,76021 Karlsruhe,Germany  T:(+49)721 608-26026 F:-926026

More information about the OpenIndiana-discuss mailing list