Hello, I'd like to check for any guidance about using zfs on iscsi storage appliances. Recently I had an unlucky situation with an unlucky storage machine freezing. Once the storage was up again (rebooted) all other iscsi clients were happy, while one of the iscsi clients (a sun solaris sparc, running Oracle) did not mount the volume marking it as corrupted. I had no way to get back my zfs data: had to destroy and recreate from backups. So I have some questions regarding this nice story: - I remember sysadmins being able to almost always recover data on corrupted ufs filesystems by magic of superblocks. Is there something similar on zfs? Is there really no way to access data of a corrupted zfs filesystem? - In this case, the storage appliance is a legacy system based on linux, so raids/mirrors are managed at the storage side its own way. Being an iscsi target, this volume was mounted as a single iscsi disk from the solaris host, and prepared as a zfs pool consisting of this single iscsi target. ZFS best practices, tell me that to be safe in case of corruption, pools should always be mirrors or raidz on 2 or more disks. In this case, I considered all safe, because the mirror and raid was managed by the storage machine. But from the solaris host point of view, the pool was just one! And maybe this has been the point of failure. What is the correct way to go in this case? - Finally, looking forward to run new storage appliances using OpenSolaris and its ZFS+iscsitadm and/or comstar, I feel a bit confused by the possibility of having a double zfs situation: in this case, I would have the storage zfs filesystem divided into zfs volumes, accessed via iscsi by a possible solaris host that creates his own zfs pool on it (...is it too redundant??) and again I would fall in the same previous case (host zfs pool connected to one only iscsi resource).
Any guidance would be really appreciated :) Thanks a lot Gabriele. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
