Jesus Cea wrote: > Darren J Moffat wrote: > > Why would you do that when it would reduce your protection > and ZFS boot > > can boot from a mirror anyway. > > I guess ditto blocks would be protection enough, since the > data would be > duplicated between both disks. Of course, backups are your friend.
I asked almost the exact same question when I first heard about ditto blocks. (See http://mail.opensolaris.org/pipermail/zfs-discuss/2007-May/040596.html and followups) There are 2 key differences between ditto blocks and mirrors: 1) The ZFS pool is considered "unprotected". That means a device failure will result in a kernel panic. 2) Ditto block separation is not enforced. The allocator tries to keep the second copy "far" from the first one, but it is possible that both copies of your /etc/passwd file are on the same VDEV. This means that a device failure could result in real loss of data. It would be really nice if there was some sort of enforced-ditto-separation (fail w/ device full if unable to satisfy) but that doesn't exist currently. --Joe _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
