It is not uncommon that hardware vendors have to fix their array controller firmware. In this case it is HP’s P2000 G3 firmware for the FC/iSCSI combined models. Again it is a fix for problems as a result of customers using bigger clusters. Here we have a problem with Windows Server 2008 R2 clusters which surfaces with bigger clusters, long IQN names and a maximum of the space available for SCSI-3 reservations. Haven’t we seen this kind of trouble before. I can assure you that admins of Hyper-V R2 clusters surpassing these limits weren’t all that happy.
Using a long IQN name for iSCSI initiators may lead to issues while using SCSI-3 reservations and Persistent Group Reservations, particularly when trying to create large clusters with multiple paths to each LUN. A predefined area is used to store SCSI-3 reservation keys for each initiator path to each LUN and, when a large number of IQN entries are attempted to be stored, the array can run out of space in this area. This issue is dependent on the number of nodes and the number of paths per node accessing individual LUNs. This issue has been seen during the cluster validation process on Windows 2008 R2 clusters with 16 nodes, where each node had 4 paths to each LUN of the array.