Cannot browse datastore in Vsphere 4 with ESX 4 Server

[walsall]

We have a dual HP EVA SAN with dual C7000 Blade enclosures with ESX 4 servers. I have set up disk on the SAN and presented to an ESX 4 Server and installed a virtual machine and everything works fine. I then set up a DR Group on the SAN and did a failover of the disk. The disk can be seen by the failover ESX 4 Server, but I cannot view anything on the datastore.

Is there anything I have to do in order for the virtual machines to be seen on this disk?

Many thanks

[beyondvm]

can you give a quick diagram as to how your environment is connected? I am not sure what you mean by dual SAN, 2 seperate SANs or 2 SP, same with dual c7ks.

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[dmauder]

Hi Walsall:

If I'm understanding your question correctly, you used some sort of array-based replication function to fail the original LUN over to a DR LUN. Is that correct? In other words, you're trying to present a "snapshot" or clone of the original SAN volume back to your ESX server. If so, you might be running into an issue with the disk signature which is why you can't see anything on the datastore. In ESX 3.5, you had to enable the LVM.EnableResignature parameter on your ESX server(s). In vSphere however, they changed it a bit. This thread discusses how to do it.

http://communities.vmware.com/thread/211404

If I'm way off base here, then I appologize and will need more information on your setup.

Dave

[walsall]

Thanks for the reply beyondvm

I can clarify the design further (will do a drawing if you require any further info):

Two datacentres. In each datacentre there is an HP EVA 4400 and a c7000 enclosure with 16 HP BL460 servers. The datacentres are connected by a 100MB leased line with an MPX 110 at each site for FCIP replication. In datacentre1 I there is an ESX 4 blade server with a SAN disk presented to it. On the disk are a few virtual machines. On the SAN Management I have created a DR Group which includes the disk. The disk has successfully replicated and appears on the SAN in datacentre2. I have presented the replicated disk to an ESX 4 Server in datacentre2. I have failed over the DR Group and the disk in datcentre1 disappears in on the storage in VSphere and appears in the storage on the ESX 4 Server in datacentre 2. However, I cannot view the virtual machines when I browse the datastore.

I have failed over disks successfully on a Windows 2008 Server so I know that the replication does work.

Hope this helps.

[dmauder]

Sounds like you're definitely running into a disk signature issue... In the below PDF document, search for "Mounting VMFS Datastores with Existing Signatures":

http://www.vmware.com/pdf/vsphere4/r40/vsp_40_san_cfg.pdf

Dave

[walsall]

Dave

When trying to unmount a datastores I am right clicking the datastore, but 'unmount' does not appear. Any thoughts?

[dmauder]

Had you previoiusly mounted the datastore and let ESX resignature it? If so, that is probably why. You can only unmount:

1. NFS datastores, and

2. VMFS datastore copies mounted without resignaturing

Dave

[walsall]

Dave

When I do the disk failover the datastore automatically disappears from the original host and appears in the fail over host. I don't actually do anything regarding adding storage etc as the host seem to configure the storage automatically.

[dmauder]

Oh, OK. The way I read your first message, it sounded like you were trying to present the original LUN and the failover (DR) LUN to the same host. Based on that document I attached to the thread earlier, you would still need to resignature the failover copy of the LUN. I believe all you would need to do is go through the "Add Storage" process and tell it to use the existing signature. I did this recently at a customer site, but we were presenting the failover copy of the LUN back to the same ESX host.

-Dave

Message was edited by: dmauder to correct my original answer

[walsall]

Dave

Thanks for your help. It's all working now.

I realised also that I had made a mistake with the LUN ID's. On the original disk it was LUN ID 2, but when the replicated disk was presented to the failover server it had LUN ID 3. The storage would appear, but I couldn't view the datastore. I did another test with a disk set at LUN ID 10 and then the replicated disk was presented to the failover server with LUN ID 10 and I could browse the datastore.