Generally, mirrors resilver MUCH faster than RAIDZ, and you only lose redundancy on that stripe, so combined, you're much closer to RAIDZ2 odds than you might think, especially with hot spare(s), which I'd reccommend.
When you're talking about IOPS, each stripe can support 1 simultanious user. Writing: Each RAIDZ group = 1 stripe. Each mirror group = 1 stripe. So, 216 drives can be 24 stripes or 108 stripes. Reading: Each RAIDZ group = 1 stripe. Each mirror group = 1 stripe per drive. So, 216 drives can be 24 stripes or 216 stripes. Actually, reads from mirrors are even more efficient than reads from stripes, because the software can optimally load balance across mirrors. So, back to the original poster's question, 9 stripes might be enough to support 5 clients, but 216 stripes could support many more. Actually, this is an area where RAID5/6 has an advantage over RAIDZ, if I understand correctly, because for RAID5/6 on read-only workloads, each drive acts like a stripe. For workloads with writing, though, RAIDZ is significantly faster than RAID5/6, but mirrors/RAID10 give the best performance for all workloads. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
