Date: Tue, 4 Oct 2011 18:09:12 +0200 From: Olivier Smedts <olivier@gid0.org> To: Paul Mather <paul@gromit.dlib.vt.edu> Cc: freebsd-current@freebsd.org Subject: Re: Strange ZFS filesystem corruption Message-ID: <CABzXLYOsXWxR8u2RvuVekQ4%2BgwPQKT6C1dSasQoAUdGY0VBMjQ@mail.gmail.com> In-Reply-To: <8B59D754-9062-4499-9873-7C2167622032@gromit.dlib.vt.edu> References: <8B59D754-9062-4499-9873-7C2167622032@gromit.dlib.vt.edu>
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2011/10/3 Paul Mather <paul@gromit.dlib.vt.edu>:
> I know ZFS does not have a fsck utility ("because it doesn't need one":),=
but does anyone know of any way of fixing this corruption short of destroy=
ing the pool, creating a new one, and restoring from backup? =A0Is there so=
me way of exporting and re-importing the pool that has the side-effect of d=
oing some kind of fsck-like repairing of subtle corruption like this?
But there is the ZFS debugger, "zdb" !
I can't really help you with that because I never had a corrupted
zpool, but if you search on the lists for up to a year or so, you'll
find some useful commands to inspect and destroy corrupted objects.
Usage: zdb [-CumdibcsDvhL] poolname [object...]
zdb [-div] dataset [object...]
zdb -m [-L] poolname [vdev [metaslab...]]
zdb -R poolname vdev:offset:size[:flags]
zdb -S poolname
zdb -l [-u] device
zdb -C
Dataset name must include at least one separator character '/' or '@'
If dataset name is specified, only that dataset is dumped
If object numbers are specified, only those objects are dumped
Options to control amount of output:
-u uberblock
-d dataset(s)
-i intent logs
-C config (or cachefile if alone)
-h pool history
-b block statistics
-m metaslabs
-c checksum all metadata (twice for all data) blocks
-s report stats on zdb's I/O
-D dedup statistics
-S simulate dedup to measure effect
-v verbose (applies to all others)
-l dump label contents
-L disable leak tracking (do not load spacemaps)
-R read and display block from a device
Below options are intended for use with other options (except -l):
-A ignore assertions (-A), enable panic recovery (-AA) or both (-AA=
A)
-F attempt automatic rewind within safe range of transaction groups
-U <cachefile_path> -- use alternate cachefile
-X attempt extreme rewind (does not work with dataset)
-e pool is exported/destroyed/has altroot/not in a cachefile
-p <path> -- use one or more with -e to specify path to vdev dir
-P print numbers parsable
-t <txg> -- highest txg to use when searching for uberblocks
Specify an option more than once (e.g. -bb) to make only that option verbos=
e
Default is to dump everything non-verbosely
--=20
Olivier Smedts=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=A0 _
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
=A0 ASCII ribbon campaign ( )
e-mail: olivier@gid0.org=A0 =A0 =A0 =A0 - against HTML email & vCards=A0 X
www: http://www.gid0.org=A0 =A0 - against proprietary attachments / \
=A0 "Il y a seulement 10 sortes de gens dans le monde :
=A0 ceux qui comprennent le binaire,
=A0 et ceux qui ne le comprennent pas."
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