Date: Fri, 27 Jul 2007 10:32:18 +0100 (BST) From: "Mark Powell" <M.S.Powell@salford.ac.uk> To: freebsd-fs@freebsd.org Subject: Breaking raidz and zpool bug? Message-ID: <20070727100039.V68220@rust.salford.ac.uk>
next in thread | raw e-mail | index | archive | help
Hi, Have a machine with two identical drives ad[01]. Each have a 4GB slice1 and the rest as slice 2. Slice 1 contains a gmirrored ufs /boot and swap. Slice2 I foolishly raidz'ed and put / on there. All works well. I realised the error of making a raidz of only 2 drives and wanted to convert this setup to gmirror without any backup/restore or pulling of drives to force them to error. I assume the difficulty with doing this is from deliberate safeguards to prevent data lose in normal usage? 1st I needed to break the raidz, stop it using one of the drives, so I can make the mirror on it. I thought I could just wipe ad1s2, but I am prevented from doing that cos it's being used by zfs. Even with kern.geom.debugflags=16. I couldn't change the partition details using fdisk for ad1s2 as it doesn't allow it for partitions in use. So i blanked sector 0 on ad1 and rebooted. zpool status showed the raidz as degraded. I thought I'd then create a zpool mirror on ad1s2, but of course I can't cos it's still part of the raidz. I could find no way to remove ad1s2 from the raidz. zpool detach is only for hot spares. I tried to get around the problems of the system not letting me do anything with ad1s2, by creating an identical ad1s3 and then changing the slice type of ad1s2 to 1 (DOS FAT 16-bit). I rebooted, but the zfs root would not mount. I booted into a test enviroment and zpool status told me the worst that no replicas could be found. At first I assumed I'd made a mess of something, but after reflection I was sure I'd not touched ad0. I changed the type of ad1s2 back to FreeBSD 165 and the zfs root worked fine again albeit in the degraded state. It shouldn't be possible to break a raidz simply by changing the slice type? Is this a bug? And does anyone have ideas for what I was trying? Cheers. -- Mark Powell - UNIX System Administrator - The University of Salford Information Services Division, Clifford Whitworth Building, Salford University, Manchester, M5 4WT, UK. Tel: +44 161 295 4837 Fax: +44 161 295 5888 www.pgp.com for PGP key
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20070727100039.V68220>