HP AiO iSCSI and Citrix Xenserver

A couple of our clients have HP AiO1200 iSCSI systems. These are nice enough units, especially for entry level iSCSI SANs. They’re in a slightly modified HP DL320s chassis, and run Windows 2003 Storage Server, as well as some custom built HP management tools.

I’ve never had an easy run when dealing with their iSCSI target and the open-scsi stack used by Citrix Xenserver. The first problem I had was that the management tools don’t support multiple initiators connecting to the same target LUN. They don’t actually stop you, but it seems that you need to hold your tongue just right to allow multiple initiators connecting to the one target. If you don’t hold it just right, the admin tools will let you do it, but it won’t actually work.[1]

The second problem I had is that Xenserver just refuses to connect, saying “Your Target is probably misconfigured”. There’s not really a lot of configuration you can do with an iSCSI target, so I’m perplexed here. Digging deeper:

[code]

# iscsiadm -m discovery -t st -p 1.2.3.4
1.2.3.4:3260,1 iqn.1991-05.com.microsoft:storage-iqn.xen-osdata-target
[/code]

It seems that iscsiadm can see everything fine!. I tried adding the target via the cli:

[code]
# xe sr-create host-uuid=f3b260ab-f8b9-4b52-980d-7b7e93ab8dcf content-type=user name-label=AIO_OSDATA shared=true type=lvmoiscsi device-config-targetIQN=iqn.1991-05.com.microsoft:storage-iqn.xen-osdata-target device-config-target=1.2.3.4

Error code: SR_BACKEND_FAILURE_107
Error parameters: , The SCSIid parameter is missing or incorrect, \
< ?xml version="1.0" ?>
iscsi-target
LUN
vendor
HP
/vendor
LUNid
0
/LUNid
size
42949672960
/size
SCSIid
360003ff646c289389ea2e31c1d419930
/SCSIid
/LUN
/iscsi-target
[/code]

Unlike the error messages you get in the GUI, that one is quite helpful[2] It tells us we’re missing a SCSIid parameter, and then lists a SCSIid parameter to try:

[code]
xe sr-create host-uuid=f3b260ab-f8b9-4b52-980d-7b7e93ab8dcf content-type=user name-label=AIO_OSDATA shared=true type=lvmoiscsi device-config-targetIQN=iqn.1991-05.com.microsoft:storage-iqn.xen-osdata-target device-config-target=1.2.3.4 device-config-LUNid=1 device-config-SCSIid=360003ff646c289389ea2e31c1d419930
[/code]

And our iSCSI target was happily added. I’m not entirely sure the LUNid parameter is required, this post suggests it isn’t. I found a couple of other posts on the forums which suggest that using the CLI for these tasks should be your first attempt.

[1] Where “work” means “actually let you connect more than one initiator at a time”
[2] Although, being full of less than and greater than signs, doesn’t want to display nicely in wordpress. So it’s a bit sanitised