On Fri, 25 Jul 2008, Matt Wreede wrote: > Now, here is the important question: Does mirroring provide a > performance boost, or is it simply a way to provide redundancy? That
Mirroring provides a performance boost for reads since a read can be done from either side of the mirror. Theoretically you could get twice the read performance but the actual boost depends on many factors so it is likely to be somewhat less. Since mirrors are very simple, ZFS is able to schedule reads across disks quite effectively. I see a quite considerable boost here. Besides the boost due to mirrors, ZFS load-shares across VDEVs so there is also a boost from more VDEVs. > is, if I go ahead and force-add the RAID-5 arrays, without mirroring > them, I'll have 6 usable drives; double the storage, but ZFS won't Always keep in mind that the pool can be no stronger than its weakest VDEV. If any VDEV in the pool fails, then the whole pool fails. Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
