On Tue, February 10, 2009 23:43, Uwe Dippel wrote: > 1. Can the relevant people confirm that drives might turn dead when > leaving a pool at unfortunate moments? Despite of complete physical > integrity? [I'd really appreciate an answer here, because this is what I > am starting to implement here: ZFS on USB drives.] > 2. Are those drives in unrecoverable state passing their > integrity/diagnosis tests (r/w)? > 3. If what has been mentioned, that a pool is an entity like RAID in > between and hurting the pool might as well destruct data, if this is the > case, can this destruction of a pool not also happen within the confines > of a server, without any physical yanking of the drive, by a dying > controller?
Seems like a power failure, controller failure, or processor failure could all produce the equivalent of yanking a USB cable. As could a cat knocking an external drive off the desk :-). All of those things are real-world issues that we must contend with. The two hardware failures are entirely possible even in a top-end commercial machine-room installation. (For that matter, the power failure is, too; I've seen places where the UPS came on fine when the power failed, and the generator cut in fine before the UPS failed...and then the automatic fail-BACK failed, and everything went dark when the generator ran out of fuel). I confess to not being adequately reassured right now that my external USB backup disks are reasonably secure. This all-or-nothing behavior of ZFS pools is kinda scary. Turns out I'd rather have 99% of my data than 0% -- who knew? :-) I'd much rather have 100.00% than either of course, and I'm running ZFS with mirroring, and doing regular backups, because of that. -- David Dyer-Bennet, d...@dd-b.net; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
