Hello,

I'm having an issue setting up a failover cluster in Windows Server 2012 R2 with iSCSI storage and I suspect the cause is having servers with duplicate session identifiers.

I am using the inbuilt iSCSI Initiator with MPIO and MCS to connect to a target. I can connect one server to the target without any issue, but when I go to connect the second I get the error "Invalid Session ID". Deleting and recreating the connection on the 2nd server a couple times fixes that error and allows it to connect. Why? Well from what I can tell its because each time I create a new session it gets a new ID. The last digit increases so I end up with Server 1 having two sessions with the final digit being 1 and 2; and Server 2 having 3 and 4.

This is too fiddley so I think something is wrong somewhere. I thought each initiator should have its own unique session IDs.

The iSCSI target IS configured to allow multiple concurrent connections. It has worked fine for me previously, but since setting up a new 2012 R2 environment it no longer works.

Even after I fiddle around with the session IDs to make sure each initiator is connecting with a unique one, once I setup the shared storage component in the failover cluster the iSCSI configuration breaks and I end up having a cluster of 2 servers both unable to connect to the storage.

Has anyone seen this before? Is there any way to reset the session IDs to generate a whole new string? Have I missed something completely?

Any advice would be greatly appreciated.

Cheers

First thing I would try - drop MC/S as this config has zero sense combined with MPIO either way. See:

http://scst.sourceforge.net/mc_s.html

http://arstechnica.com/civis/viewtopic.php?t=1152422

Then I would contact SAN vendor and discuss the issue. Maybe they do have updated DSM for R2 or different target-side settings...

Hi,

About the storage question please post to the File Services and Storage forum.

File Services and Storage

http://social.technet.microsoft.com/Forums/en-US/home?forum=winserverfiles

Thanks for your understanding and support.

Thanks VR38DETT,

I've tried dropping the MC/S (basically, I had the IPv4 and IPv6 addresses for each NIC connect to the corresponding NIC on the NAS in each MPIO session) but still the problem remains. I've even taken MPIO and MC/S out of the picture all together and just had both servers connect to the target with a single connection each and they still fight with each other.

I'll contact the vendor but I've never had to install a DSM before ever for this task. I still think this has something to do with Windows.