Are these issues something to watch out for on Solaris 11 as well? Thx in 


On Apr 9, 2012, at 12:43 PM, Marion Hakanson wrote:

> 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
>> 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

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