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

Chris Worley worleys at gmail.com
Mon Oct 11 11:37:20 PDT 2010


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?

Thanks,

Chris



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