Odd variation in SATA speeds at enumeration time

[JaimieV]

I was looking through /var/log/messages for something else, and spotted that my disks in the Xyratex disk shelf (dumb SAS expander, SATA-3 disks) are being enumerated at varying SATA speeds. Is this anything to care about? Being 4TB 3.5" HDDs they're unlikely to individually go much higher than 150MB/sec, and CQ is enabled on each drive so that's the main thing, but having the same-model Toshibas running at 150 or 300 or 600, or same-model Seagates at 300/600 for no apparent reason seems wrong.

I haven't tried anything yet, since it probably doesn't actually matter. If I do, is there some command to show the speed they're connected at currently? I'd prefer not to reboot every time to try, the machine takes about six minutes and it's very boring to experiment that way, even if I just pull/reinsert with the pool offline.

Trimmed snippet from boot time:

Code:

Jun 23 12:05:10 Sisyphus ses0 at mps0 bus 0 scbus0 target 15 lun 0
Jun 23 12:05:10 Sisyphus ses0: <XYRATEX HB-1235-E6EBD 221a> Fixed Enclosure Services SPC-3 SCSI device
Jun 23 12:05:10 Sisyphus ses0: 600.000MB/s transfers
Jun 23 12:05:10 Sisyphus ses0: Command Queueing enabled
Jun 23 12:05:10 Sisyphus ses0: SCSI-3 ENC Device
Jun 23 12:05:10 Sisyphus da8 at mps0 bus 0 scbus0 target 29 lun 0
Jun 23 12:05:10 Sisyphus da8: <ATA ST4000NM0033-9ZM GA6C> Fixed Direct Access SPC-4 SCSI device
Jun 23 12:05:10 Sisyphus da8: 600.000MB/s transfers
Jun 23 12:05:10 Sisyphus da3: <ATA TOSHIBA MG03ACA4 FL2H> Fixed Direct Access SPC-4 SCSI device
Jun 23 12:05:10 Sisyphus da3: 600.000MB/s transfers
Jun 23 12:05:10 Sisyphus da6: <ATA ST4000NM0033-9ZM GA6E> Fixed Direct Access SPC-4 SCSI device
Jun 23 12:05:10 Sisyphus da6: 600.000MB/s transfers
Jun 23 12:05:10 Sisyphus da4: <ATA TOSHIBA MG03ACA4 FL2H> Fixed Direct Access SPC-4 SCSI device
Jun 23 12:05:10 Sisyphus da4: 300.000MB/s transfers
Jun 23 12:05:10 Sisyphus da5: <ATA ST4000NM0033-9ZM GA6C> Fixed Direct Access SPC-4 SCSI device
Jun 23 12:05:10 Sisyphus da5: 300.000MB/s transfers
Jun 23 12:05:10 Sisyphus da2: <ATA TOSHIBA MG03ACA4 FL2H> Fixed Direct Access SPC-4 SCSI device
Jun 23 12:05:10 Sisyphus da2: 150.000MB/s transfers
Jun 23 12:05:10 Sisyphus da7: <ATA TOSHIBA MG03ACA4 FL2H> Fixed Direct Access SPC-4 SCSI device
Jun 23 12:05:10 Sisyphus da7: 600.000MB/s transfers
Jun 23 12:05:10 Sisyphus da1: <ATA ST4000NM0033-9ZM GA6E> Fixed Direct Access SPC-4 SCSI device
Jun 23 12:05:10 Sisyphus da1: 300.000MB/s transfers
Jun 23 12:05:10 Sisyphus da0: <ATA ST4000NM0033-9ZM GA6C> Fixed Direct Access SPC-4 SCSI device
Jun 23 12:05:10 Sisyphus da0: 600.000MB/s transfers

 

[JaimieV]

On a reboot (U5 update) I note that the same drives take the same speeds as above.

During my next reboot I'll shuffle some disks around and see if the speed sticks with the shelf slot, the disk, or the daX device.