bin/121366: [zfs] [patch] Automatic disk scrubbing from periodic(8)

[Pawel Jakub Dawidek]

The following reply was made to PR bin/121366; it has been noted by GNATS.

From: Pawel Jakub Dawidek <pjd at FreeBSD.org>
To: Stefan Moeding <sm at kill-9.net>
Cc: FreeBSD-gnats-submit at FreeBSD.org
Subject: Re: bin/121366: [zfs] [patch] Automatic disk scrubbing from periodic(8)
Date: Mon, 7 Sep 2009 16:58:05 +0200

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 On Tue, Mar 04, 2008 at 08:46:51PM +0100, Stefan Moeding wrote:
 >=20
 > >Number:         121366
 > >Category:       bin
 > >Synopsis:       [zfs] [patch] Automatic disk scrubbing from periodic(8)
 > >Confidential:   no
 > >Severity:       non-critical
 > >Priority:       low
 > >Responsible:    freebsd-bugs
 > >State:          open
 > >Quarter:       =20
 > >Keywords:      =20
 > >Date-Required:
 > >Class:          change-request
 > >Submitter-Id:   current-users
 > >Arrival-Date:   Tue Mar 04 20:10:01 UTC 2008
 > >Closed-Date:
 > >Last-Modified:
 > >Originator:     Stefan Moeding
 > >Release:        FreeBSD 7.0-STABLE i386
 > >Organization:
 > >Environment:
 > System: FreeBSD elan.setuid.de 7.0-STABLE FreeBSD 7.0-STABLE #23: Sat Mar=
   1 14:17:18 CET 2008 root at elan.setuid.de:/usr/obj/usr/src/sys/ELAN i386
 > >Description:
 >=20
 > The ZFS Best Practices Guide recommends disk scrubbing on a regular
 > basis.  The attached file fits into the periodic(8) framework to start
 > a weekly scrub.  It will look at all pools and choose one of them on a
 > round-robin basis depending on the date of the last scrub/resilver
 > unless there is already a scrub or resilver running.
 >=20
 > The script should probably be installed to run at the end the weekly
 > schedule to avoid I/O contention from scrubbing and other weekly scripts.
 >=20
 > The new periodic(8) switch 'weekly_zfs_scrubbing_enable' is introduced.
 >=20
 > One drawback: ZFS seems to forget the time of a scrub/resilver when
 > shutting down.  On machines with regular reboots and multiple pools
 > the script will probably pick the same pool every time.
 
 Maybe you can use user properties to remember time of last automatic
 scrub? A user property has to contain ':' in its name, eg.:
 
 	# zfs set org.freebsd:lastscrub=3D`date "+%s"` pool
 	# zpool scrub pool
 
 You can obtain it later with:
 
 	# zfs get -H -o value org.freebsd:lastscrub system
 
 It can be removed (if needed) with:
 
 	# zfs inherit org.freebsd:lastscrub system
 
 If you like the idea, would you also like to update your script to use it?
 
 --=20
 Pawel Jakub Dawidek                       http://www.wheel.pl
 pjd at FreeBSD.org                           http://www.FreeBSD.org
 FreeBSD committer                         Am I Evil? Yes, I Am!
 
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