HP StorageWorks P2000 Firmware Release Notes page 6

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.
Number of paths per cluster node
1
1 223
2 223
3 223
4 223
5 223
6 223
Number
7 223
of
cluster
8 223
nodes
9 223
10 223
11 223
12 223
13 223
14 223
15 223
16 223
6
Maximum IQN Character Length
2 3 4
223 223 223
223 223 223
223 223 223
223 223 223
223 223 176
223 197 144
223 166 121
223 144 104
197 126 90
176 112 80
158 100 71
144 90 64
131 82 57
121 75 52
112 69 48
104 64 44
5 6 7
223 223 223
223 223 223
223 197 166
176 144 121
137 112 93
112 90 75
93 75 62
80 64 52
69 55 44
60 48 38
53 42 33
48 37 29
43 33 26
38 29 23
35 26 20
32 24 18
8
223
223
144
104
80
64
52
44
37
32
27
24
20
18
16
14