> If I'm not mistaken, a 3-way mirror is not > implemented behind the scenes in > the same way as a 3-disk raidz3. You should use a > 3-way mirror instead of a > 3-disk raidz3.
RAIDZ2 requires at least 4 drives, and RAIDZ3 requires at least 5 drives. But, yes, a 3-way mirror is implemented totally differently. Mirrored drives have identical copies of the data. RAIDZ drives store the data once, plus parity data. A 3-way mirror gives imporved redundancy and read performance, but at a high capacity cost, and slower writes than a 2-way mirror. It's more common to do 2-way mirrors + hot spare. This gives comparable protection to RAIDZ2, but with MUCH better performance. Of course, mirrors cost more capacity, but it helps that ZFS's compression and thin provisioning can often offset the loss in capacity, without sacrificing performance (especially when used in combination with L2ARC). -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
