MPIO DSM and ActiveOptimized state

[Nelson Jeppesen]

We have a EVA8400 and EVA4100 connected to Windows 2003, 2008 and ESXi servers.

The problem is that the Windows servers with the latest MPIO DSM installed are only sending reads to the active controller. Writes are being sent to both controllers according to EVAperf.

ESXi with with round robin is sending ALL traffic to just the owning controller.

As a result the SQL IO is FASTER in a VM in ESXi, as opposed to a psychical 2003 or 2008 server.

What is wrong with Windows MPIO DSM? Why don't I see half the paths as ActiveOptimized? I just see ALL paths as active.

All LUN paths on windows show up as Active
All LUNs are set to 'no preference' path on CV
All MPIO DSM and EVA firmware is up to the latest
ALB and default load balancing is enabled on all servers
Both the EVA8400 and EVA4100 act the same
All servers are zoned the same.

[Virtual Craig]

With Windows MPIO - with ALB set then reads to the owning controller and writes to both contolers is expected. The write cache data is mirroed between controllers for redundancy, obviosuly we don't need to worry about that with reads.

Look at how each LUN is perfoming and spread busy LUNs over both controllers (keeping a good balance). You can do this by setting LUN preference within CV.