I have several MD3620i storage arrays. My iscsi hosts are all Server 2012 R2. I have noticed some odd behavior with the MPIO settings after I upgraded the storage array controller to 7.84.56.60.
I am concerned because I have seen a virtual disk randomly migrate to the failover controller, and throw a warning stating it is not on its preferred controller.
I am using the RDVD 5.1..0.9 install DVD to install the Dell MPIO drivers/configuration.
My iscsi network config is exactly what is shown in the dell best practices guides. Two dedicated NICs on each server cabled to two dedicated iscsi 10gig switches. Four paths are built between each server and the array, one for each port on the array. My virtual disks are configured under disk groups and I have a windows host group that is defined to access the virtual disks.
In the MPIO window (Iscsi initiator, select target, Devices button, MPIO button) the load balance policy is set to Least Queue Depth. There are four paths listed, however they are all listed as active. I've been using the MD3xxxx series for awhile, and this has always been two active (to the controller that is primary on the volume), and two standby (to the failover controller).
The same server is connected to another MD3620i running 7.80.41.60 firmware, and has the standard two active/two standby paths.
The MPIO configuration snapshot shows the following for the MD3620i running 7.84.56.60:
MPIO Disk6: 04 Paths, Least Queue Depth, Implicit and Explicit
Supported Load Balance Policies: FOO RRWS LQS WP
4 Paths are listed, two are Active/Optimized, and two are Active/Unoptimized. The controller state on all four is Active.
The MPIO configuration snapshot shows the following for the MD3620i running 7.80.41.60:
MPIO Disk1: 04 Paths, Least Queue Depth, Implicit and Explicit
Supported Load Balance Policies: FOO RRWS LQD WP
4 Paths are listed, two are Active/Optimized, and two are Standby. Controller state on all four is Active.
So why does the latest firmware make the two paths through the failover controller "Active/Unoptimized" instead of "standby"? I've had these arrays in operation for a couple years without any issues, first with 2008 R2, and now with 2012 R2 for the past 9 months. I have only recently upgraded one of my MD3620i's to 7.84.56.60.
Thanks for any help or suggestions.