Hi Toby, My understanding on the subject of SATA firmware reliability vs. FC/SCSI is that its mostly related to SATA firmware being a lot younger. The FC/SCSI firmware that's out there has been debugged for 10 years or so, so it has a lot fewer hiccoughs. Pillar Data Systems told us once that they found most of their SATA "failed disks" were just fine when examined, so their policy is to issue a RESET to the drive when a SATA error is detected, then retry the write/read and keep trucking. If they continue to get SATA errors, then they'll fail the drive.
Looking at the latest Engenio SATA products, I believe they do the same thing. Its probably unfair to expect defect rates out of SATA firmware equivalent to firmware that's been around for a long time...particularly with the price pressures on SATA. SAS may suffer the same issue, though they seem to have 1,000,000 MTBF ratings like their traditional FC/SCSI counterparts. On a side-note, we experienced a path failure to a drive in our SATA Engenio array (older model), simply popping the drive out and back in fixed the issue...haven't had any notifications since. A RESET and RETRY would have been nice behavior to have, since popping and reinserting triggered a rebuild of the drive. Best Regards, Jason On 12/19/06, Toby Thain <[EMAIL PROTECTED]> wrote:
On 19-Dec-06, at 2:42 PM, Jason J. W. Williams wrote: >> I do see this note in the 3511 documentation: "Note - Do not use a >> Sun StorEdge 3511 SATA array to store single instances of data. It >> is more suitable for use in configurations where the array has a >> backup or archival role." > > My understanding of this particular scare-tactic wording (its also in > the SANnet II OEM version manual almost verbatim) is that it has > mostly to do with the relative unreliability of SATA firmware versus > SCSI/FC firmware. That's such a sad sentence to have to read. Either prices are unrealistically low, or the revenues aren't being invested properly? --Toby > Its possible that the disks are lower quality SATA > disks too, but that was not what was relayed to us when we looked at > buying the 3511 from Sun or the DotHill version (SANnet II). > > > Best Regards, > Jason > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
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