On Apr 8, 2010, at 6:19 PM, Daniel Carosone wrote: > > As for error rates, this is something zfs should not be afraid > of. Indeed, many of us would be happy to get drives with less internal > ECC overhead and complexity for greater capacity, and tolerate the > resultant higher error rates, specifically for use with zfs (sector > errors, not overall drive failure, of course). Even if it means I > need raidz4, and wind up with the same overall usable space, I may > prefer the redundancy across drives rather than within.
Disagree. Reliability trumps availability every time. And the problem with the availability provided by redundancy techniques is that the amount of work needed to recover is increasing. This work is limited by latency and HDDs are not winning any latency competitions anymore. To combat this, some vendors are moving to an overprovision model. Current products deliver multiple "disks" in a single FRU with builtin, fine-grained redundancy. Because the size and scope of the FRU is bounded, the recovery can be optimized and the reliability of the FRU is increased. From a market perspective, these solutions are not suitable for the home user because the size and cost of the FRU is high. It remains to be seen how such products survive in the enterprise space as HDDs become relegated to backup roles. -- richard ZFS storage and performance consulting at http://www.RichardElling.com ZFS training on deduplication, NexentaStor, and NAS performance Las Vegas, April 29-30, 2010 http://nexenta-vegas.eventbrite.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
