On Thursday 25 October 2007, Steven Alligood wrote: > Without having any more information than this email (was there an > earlier one I missed?), I would grasp at the straw that the different > sides of the array are going through different controllers (either > within the array or in the attached computer), and possibly even that > the SAS drives are possibly causing some form of congestion or > performance bottleneck on their controller for all of the SATA drives, > or rather, the array isn't very good at mixing both types on the same > controller and keeping up the expected speeds.
There is a single sas controller, with a single sas cable to a single drive bay enclosure with 12 bays. I always use software raid. I am only mirroring sas-to-sas or sata-to-sata, matched drives. In fact all 8 of the sata drives are the exact same model, from the same shipment. It is an lsi sas controller, lspci shows: SCSI storage controller: LSI Logic / Symbios Logic SAS1068 PCI-X Fusion-MPT SAS (rev 01) The sata drives are 320GB 7200rpm hitachi deskstar. Does any of this info help shed insight to my puzzle? All of the drives are idle--none are in service yet. It makes no sense to me why I would see such significantly different performance characteristics based solely on the specific pairing of drives. Perhaps a bios bug in the sas controller card? Something to do with how the addressing is done with sas expanders? /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
