sql-lover (4/24/2013)
The MCS policy was set to "round robin".
You use either MPIO or MCS not both, so, are you using MCS or MPIO?
MCS is specific to the Microsoft iSCSI Initiator and comprises single session\multiple connection.
MPIO uses multiple sessions.
For more info on iSCSI see my article at this link[/url].
sql-lover (4/24/2013)
The MCS policy was set to "round robin". Now, I do believe we are using the default Microsoft MPIO driver, but where can I check than on Windows and confirm? I do not remember where ...
Open the Microsoft iSCSI Initiator console, select the disk device and open the properties. You should see the MPIO button which will open the MPIO properties to view\change.
sql-lover (4/24/2013)
Also, forgot to mention and I actually was not aware about this until yesterday, we do not have two switches but only one and both nodes are connected to same switch. That actually defeats part of MPIO purpose, I think. Not sure why our IT resource made it that way.
When using storage multi pathing one would sort of hope that the hardware would be in place to support the topology otherwise a switch hardware failure will leave MPIO redundant!!
You should have more than 2 switches for your iSCSI network. A typical topolgy would have at least 2 core switches with edge switches feeding off these to provide multiple redundant paths down to your storage. This is all detailed in my article linked above.
The whole point of multi pathing is to allow Windows server to host highly available local SAN disks otherwise the OS would see the multiple paths as separate disk devices, which they are not.
With 10GBoe available you're exceeding the capabilities of a standard FC setup 😉
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