[ofw] Issue w/ Multipathing SRP in WinOF 2.3 RC4 w/ >4 drives

[Chris Worley]

On Mon, Oct 11, 2010 at 12:37 PM, Chris Worley <worleys at gmail.com> wrote:
> While multipathing helps SRP shortcomings in many respects, including
> performance, it seems Windows (W2K8R2 Standard) multipathing gets very
> confused with >4 drives.
>
> With 8 drives exported to Windows over SRP, without Multipath
> installed/configured, Windows correctly shows 8 drives and 8
> duplicates, and labels the duplicates as offline.
>
>  In configuring multipathing, the "MPIO Properties" dialog in the
> "Discover Multi-paths" tab initially shows four drives.  Add those and
> (w/o rebooting) return to the tab shows two more; add those and return
> to the tab shows the last two.  With all 8 added, reboot, and "Device
> Manager" shows 4 MPIO SRP drives (the four it showed initially in the
> "Discover Multi-paths" tab).
>
> Looking at the MPIO properties of two of those drives shows two paths
> each, the other two drives show six paths each (there are only two
> paths).  When I try to change the "Policy" from the "Round Robin"
> default to "Least Queue Depth", the two drives with two paths have no
> issue; the two drives with six paths put up an error message that
> merely describes the policy, but not any error, and the change won't
> take.
>
> I uninstalled MPIO and reinstalled it, and the same occurred.
> Strangely, after the reinstall, the "Least Queue Depth" policy stuck
> on drives I had assigned that to before... as if the uninstall didn't
> clean the registry as well as it should have.
>
> Any ideas?

Text output from Windows (you can see the four drives it allows me to
use, but the eight drives it sees):

C:\Users\Administrator>mpclaim -e

"Target H/W Identifier   "   Bus Type     MPIO-ed      ALUA Support
-------------------------------------------------------------------------
"SCST_BIOfio-71962       "   Fibre        YES          ALUA Not Supported
"SCST_BIOfio-71957       "   Fibre        YES          ALUA Not Supported
"SCST_BIOfio-41000       "   Fibre        YES          ALUA Not Supported
"SCST_BIOfio-40948       "   Fibre        YES          ALUA Not Supported

C:\Users\Administrator>mpclaim -h

"MSDSM Supported DeviceId"
-------------------------------------------------------------------------
"Vendor 8Product       16"
"SCST_BIOfio-40948       "
"SCST_BIOfio-71962       "
"SCST_BIOfio-71957       "
"SCST_BIOfio-41000       "
"SCST_BIOfio-41001       "
"SCST_BIOfio-71964       "
"SCST_BIOfio-41002       "
"SCST_BIOfio-71965       "