RAIDZ has to rebuild data by reading all drives in the group, and reconstructing from parity. Mirrors simply copy a drive.
Compare 3tb mirros vs. 9x3tb RAIDZ2. Mirrors: Read 3tb Write 3tb RAIDZ2: Read 24tb Reconstruct data on CPU Write 3tb In this case, RAIDZ is at least 8x slower to resilver (assuming CPU and writing happen in parallel). In the mean time, performance for the array is severely degraded for RAIDZ, but not for mirrors. Aside from resilvering, for many workloads, I have seen over 10x (!) better performance from mirrors. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
