Sriram, On Sun, Feb 08, 2009 at 12:04:22AM +0530, Sriram Narayanan wrote: > >From the presentation "ZFS - The last word in filesystems", Page 22 > "In a multi-disk pool, ZFS survives any non-consecutive disk failures" > > Questions: > If I have a 3 disk RAIDZ with disks A, B and C, then: > - if disk b fails, then will I be able to continue to read data if > disks A and C are still available ?
Yes, with RAIDZ, ZFS can sustain with 1 disk failure. > If I have a 4 disk RAIDZ with disks A, B, C, and D, then: > - if disks a and b fail, then I won't be able to read from the mirror > any more. Is this understanding correct ? Since, this is a RAIDZ configuration, it can sustain upto one disk failure. So, answer is "no". RAIDZ is similar to RAID-5 wrt to redundancy. > - if disks a and c fail, then I will be be able to read from disks b > and d. Is this understanding correct ? Same as above. However, if you had configured it as RAIDZ-2 then it can sustain upto 2 disk failures. The other option would be configure it as mirrored pool. And this too can sustain 2 disk failures (one in each mirror device). Hope that helps. Thanks and regards, Sanjeev > > -- Sriram > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
