Are these issues something to watch out for on Solaris 11 as well? Thx in advance…
-Anh On Apr 9, 2012, at 12:43 PM, Marion Hakanson wrote: > richard.ell...@richardelling.com said: >> We are starting to see a number of SAS HDDs that prefer logical-block to >> round-robin. I see this with late model Seagate and Toshiba HDDs. >> >> There is another, similar issue with recognition of multipathing by the >> scsi_vhci driver. Both of these are being tracked as https://www.illumos.org/ >> issues/644 and there is an alternate scsi_vhci.conf file posted in that >> bugid. > > Interesting, I just last week had a Toshiba come from Dell as a replacement > for a Seagate 2TB SAS drive; On Solaris-10, the Toshiba insisted on showing > up as 2 drives, so mpxio was not recognizing it. Fortunately I was able to > swap the drive for a Seagate, but I'll stash away a copy of the scsi_vhci.conf > entry for the future. > > >> We're considering making logical-block the default (as in above bugid) and we >> have not discovered a reason to keep round-robin. If you know of any reason >> why round-robin is useful, please add to the bugid. > > Should be fine. When I first ran into this a couple years ago, I did a > lot of tests and found logical-block to be slower than "none" (with those > Seagate 2TB SAS drives in Dell MD1200's), but not a whole lot slower. > I vaguely recall that round-robin was better for highly random, small I/O > (IOPS-intensive) workloads. > > I got the best results by manually load-balancing half the drives to one > path and half the drives to the other path. But I decided it was not > worth the effort. Maybe if there was a way to automatically do that > (with a relatively static result).... Of course, this was all tested > on Solaris-10, so your mileage may vary. > > Regards, > > Marion > > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
