Anton B. Rang wrote:
This is a difference from RAID-5. In RAID-5, small reads are more efficient than mirroring because there are more disk spindles available, and a small read usually uses only one. Small writes are less efficient than mirroring in RAID-5 because they require a pre-read phase (though only to two disks, rather than all).
I don't believe this statement is generally true. Consider the case of 4 disks. RAID-1+0 could service 4 independent read iops concurrently. RAID-5 could only service 2 independent read iops concurrently. More generally, the 2-way mirror, RAID-1+0 could always service at least 2 (>= N/2) independent read iops concurrently while RAID-5 could only service a maximum of 2 (<= int(N/2)) concurrent read iops. -- richard _______________________________________________ zfs-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
