[OpenIndiana-discuss] Mitigating the performance impact of scrub

[Udo Grabowski (IMK)]

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
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