Date: Sat, 27 Jul 2013 08:01:59 +1000 From: Peter Jeremy <peter@rulingia.com> To: Kirk Richard Holz <krh@kirkholz.com.au> Cc: freebsd-fs@freebsd.org Subject: Re: Trying to recover 2-element zfs striped (raid0) filesystem Message-ID: <20130726220159.GI86483@server.rulingia.com> In-Reply-To: <1b756c89576eb509d1197c4d9ab66fea@kirkholz.com> References: <1b756c89576eb509d1197c4d9ab66fea@kirkholz.com>
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--/NkBOFFp2J2Af1nK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2013-Jul-26 01:33:01 -0700, Kirk Richard Holz <krh@kirkholz.com.au> wrot= e: >The partition table of one of the two disks in a zfs striped (raid0)=20 >array has been corrupted. Once you recover the partition table for ada3, ZFS should be OK (as long as you haven't written too much to the pool). If zShare is your boot device, I strongly recommend booting off alternative media. Ideally, you should take full physical copies of both disks. If you are unable to remember the partition layout, you should be able to recover it by looking for the ZFS vdev labels: Each ZFS vdev has 4 256KiB labels - 2 at the start of the partition and 2 at the end of the partition so locating those will identify the start and end of the partition - if you used the entire disk for ZFS, they will be close to the start & end of the disk and "hd /dev/ada3|less" should be enough to find the first label. The first label on all my vdevs begins: 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |..............= =2E.| * 00003fd0 00 00 00 00 00 00 00 00 11 7a 0c b1 7a da 10 02 |.........z..z.= =2E.| 00003fe0 3f 2a 6e 7f 80 8f f4 97 fc ce aa 58 16 9f 90 af |?*n........X..= =2E.| 00003ff0 8b b4 6d ff 57 ea d1 cb ab 5f 46 0d db 92 c6 6e |..m.W...._F...= =2En| 00004000 01 01 00 00 00 00 00 00 00 00 00 01 00 00 00 24 |..............= =2E$| 00004010 00 00 00 20 00 00 00 07 76 65 72 73 69 6f 6e 00 |... ....versio= n.| 00004020 00 00 00 08 00 00 00 01 00 00 00 00 00 00 13 88 |..............= =2E.| 00004030 00 00 00 24 00 00 00 20 00 00 00 04 6e 61 6d 65 |...$... ....na= me| If you look at the output of "zdb -C zShare", the 'asize' value is the usable size of the vdev in bytes - the physical size is a slightly larger (~4.5MB for me) but the labels are at the end of the physical partition. For more details, see the ZFS On-Disk Specification (ondiskformat0822.pdf) --=20 Peter Jeremy --/NkBOFFp2J2Af1nK Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (FreeBSD) iEYEARECAAYFAlHy8dcACgkQ/opHv/APuIfvQQCfYsdZGPiPS0o+/HQ5fJIBl415 s0IAoIHWbhiBzZyKRv9Nvvl1GhTIDEpx =WlyL -----END PGP SIGNATURE----- --/NkBOFFp2J2Af1nK--
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