Issue: 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.
Workaround: Shorten the IQN name on the nodes.
The following formula is used to calculate the maximum IQN name length based on the number of cluster
nodes and the number of paths from each node to a LUN on the array:
Maximum IQN Character Length = [3840 / (n * p)] – 16 (Where n = number of cluster nodes
and p = number of paths per cluster node.)
NOTE: By specification, 223 is the maximum IQN length allowed.
The following table provides the calculated values based on the number of cluster nodes and the number of
paths from each node to LUN on the array.
Maximum IQN Character Length
Number of paths per cluster node
Number
of
cluster
nodes
87654321
2232232232232232232232231
2232232232232232232232232
1441661972232232232232233
1041211441762232232232234
80931121371762232232235
6475901121441972232236
526275931211662232237
445264801041442232238
37445569901261972239
323848608011217622310
273342537110015822311
24293748649014422312
20263343578213122313
18232938527512122314
16202635486911222315
14182432446410422316
6
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