Can't share VMFS datastore on iSCSI SAN between 2 ESX hosts

[thattommyhall]

I want to be able to use vmotion, I currently have 2 servers, each with 2 network cards - one connected directly to a port on the SAN and one connected to a switch on our network.

At the moment I am using software iSCSI initiator if that makes any difference.

We have quite a budget AX150SCi SAN (enough for us at the moment though)

I cannot add the VMWARE LUN as a datastore on both ESX servers at once though (by selecting storage/add storage) as it warns me it will format the target device.

It shows up as vmhba40:0:2 on server1 and vmhba40:1:1:1 on server2 if that is any help.

[masaki · Accepted solution]

I think you shouldn't add it on both ESX servers (but I could be wrong).

Add only on the first and Rescan on the second.

[thattommyhall]

I can only see "refresh" and it seems to achieve nothing.

[Erik_Zandboer]

Masaki is right; you should add the storage on one ESX box, rescan on the other.

Are you able to add the iSCSI storage on both ESX hosts? (so, remove the storage from the first, try to add storage on the second host). If not, you might want to look at the iSCSI config of both hosts for differences.

[thattommyhall]

I can add it on both.

If rescan is different to resfresh, please tell me where it is.

Cheers for answering so swiftly

[masaki]

Go under Configuration -> Storage adaptersand not Configuration -> Storage.

there choose the rescan flag

[thattommyhall]

I cant seem to attach an image file.

In storage adaptors, I have iSCSI software initiator and poweredge RAID controller and it can detect 2 LUNS on the SAN, but they are not in the data store list (I added the SAN to both ESX servers as dynamically discovered.)

[thattommyhall]

I just noticed that last post is confusing, by "image file" i just ment a jpg of the config screen.

[thattommyhall]

I found this post http://www.vmware.com/community/thread.jspa?threadID=55478&start=20&tstart=0

and thought it would solve my problem, but it did not.

The guide from EMC seems to suggest that after the scan, the VMFS partitions will be in the datastore tab, but that is not the case.

SAN configuration issue?

Do I really need to install navisphere? (both the servers can create new VMFS partitions on the LUN, just not share it,)

Is the shared LUN supposed to appear in both the servers datastores ? (I think so, that certainly makes most sense to me)

[bertdb]

your storage array needs to show that volume as the same LUN ID to both servers. If those numbers differ, you'll have problems (might be able to workaround using disallowsnapshotLUN=0).

[thattommyhall]

Would that mean putting a switch in rather than a direct cable connection to the SAN?

Each would see both SPs and I could get SP failover then, correct?

[thattommyhall]

Superb!

disallowsnapshotLUN=0 worked perfectly (I think)

Am I correct in thinking that if I dont use snapshots in the SAN I am safe?

I am about to try some vmotion, Ill post again if it works.

Thanks all, this seems a great community.

Tom

[bertdb]

you can use snapshots, but it's absolutely forbidden to show the snapshots to the ESX hosts. They have to stay hidden, because the ESX might not be able to differentiate between the original (evolved) and snapshotted (frozen) volume.

[masaki]

If you want to use your SAN software to make snapshots you must use RDM instead of LUNs.