> > Hi Ross, > > > > What about old good raid10? It's a pretty > reasonable choice for > > heavy loaded storages, isn't it? > > > > I remember when I migrated raidz2 to 8xdrives > raid10 the application > > administrators were just really happy with the new > access speed. (we > > didn't use stripped raidz2 though as you are > suggesting). > > Raid10 provides excellent performance and if > performance is a priority > then I recommend it, but I was under the impression > that resiliency > was the priority, as raidz2/raidz3 provide greater > resiliency for a > sacrifice in performance.
My experience is in line with Ross' comments. There is no question that more independent vdevs will improve IOPS, e.g. RAID10 or even a pile of RAIDZ vdevs. I have been burnt too many times to let an array get critical (no redunancy). Never, ever, ever again. With a RAID1 or RAID10, one disk loss puts the whole pool critical, just one bad sector from disaster. One prays the hot spare can be built in time. With RAIDZ, the same is true. I think of triple (or even quad) mirroring the same way as I think of RAIDZ3: it's like having prebuilt hot spares. I suspect that the IOPS problems of wide stripes are becoming mitigated by L2ARC/ZIL and that the trend will be toward wide stripes with ever higher parity counts. Sun's recent storage offerings tend to confirm this trend: slower, cheaper and bigger SATA drives fronted by SSD L2ARC and ZIL. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
