Date: Fri, 26 Mar 2021 13:41:08 +0100 From: Mathieu Chouquet-Stringer <me+freebsd@mathieu.digital> To: Michael Gmelin <freebsd@grem.de> Cc: Matt Churchyard <matt.churchyard@userve.net>, "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org>, current@freebsd.org Subject: Re: Scrub incredibly slow with 13.0-RC3 (as well as RC1 & 2) Message-ID: <YF3WZAbSp4oOJl/u@weirdfishes> In-Reply-To: <20210326132945.3274687e@bsd64.grem.de> References: <YFhuxr0qRzchA7x8@weirdfishes> <202103221515.12MFFHRK015188@higson.cam.lispworks.com> <YFi6Lwh3ISn8UMvS@weirdfishes> <YFk11A/j7URClN/l@weirdfishes> <YFm3BTK/J9XY/mCN@weirdfishes> <202103241230.12OCUqur030001@higson.cam.lispworks.com> <YFs3jFT7sEaGeQCe@weirdfishes> <33eb78e2de404a77b271880dbee4c22e@SERVER.ad.usd-group.com> <YF2raxOUeN8Y23eT@weirdfishes> <20210326132945.3274687e@bsd64.grem.de>
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On Fri, Mar 26, 2021 at 01:29:45PM +0100, Michael Gmelin wrote:
> Does tuning of
>
> - vfs.zfs.scrub_delay
> - vfs.zfs.resilver_min_time_ms
> - vfs.zfs.resilver_delay
>
> make a difference?
Only vfs.zfs.resilver_min_time_ms exists in 13 it seems.
The default values is 3000 but doubling it to 6000 doesn't change
anything. And that could make sense because it seems I'm often cpu bound
as I see the following in top (-SH):
PID USERNAME PRI NICE SIZE RES STATE C TIME WCPU COMMAND
31 root -8 - 0B 3984K CPU12 12 758:07 99.65% zfskern{dsl_scan_iss_0}
And that's on an Intel(R) Xeon(R) CPU E5-2696 v2 @ 2.50GHz with a
turbo @ 3.50GHz...
Disks are busy roughly between 30 to 50% of the time:
extended device statistics
device r/s w/s kr/s kw/s ms/r ms/w ms/o ms/t qlen %b
da2 1520 0 34974.1 0.0 0 0 0 0 1 31
da3 1469 0 35030.3 0.0 0 0 0 0 0 32
da4 1317 0 35106.6 0.0 0 0 0 0 0 42
da6 1293 0 35094.5 0.0 0 0 0 0 0 36
da7 1466 0 35032.3 0.0 0 0 0 0 0 31
da8 0 1303 0.0 34917.9 0 0 0 0 0 43
da9 1396 0 35046.4 0.0 0 0 0 0 1 34
da10 1393 0 35062.4 0.0 0 0 0 0 0 32
da8 is the disk being resilvered.
--
Mathieu Chouquet-Stringer
The sun itself sees not till heaven clears.
-- William Shakespeare --
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