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ESX 4.1 & LeftHand Failover LUNS


ESX 4.1 & LeftHand Failover LUNS


I have a scenario of a Primary & DR Site, both with equal ESX 4.1 hosts on each site.

I have created my VM infrastructure at Primary with all Datastores and VM's created.

I was testing the failover of a Datastore and the question i have is how the LUN should be presented to the ESX hosts at the DR site?

I made the DR LUN acting Primary and presented to the DR ESX Hosts. I did a scan of the iSCSI HBA's and it picked up the LUN. I then went to ADD Datastore (waited about 30 seconds for LUN to appear) but then what should i choose in regards to the LUN signature???

I tried to keep existing signature in the hope of maintaining the LUN names, however with that option only ONE ESX host out of the 3 were able to see the Datastore. The others could see the LUN in the Storage Adapters, but not the Datastore.

I also chose the GIVE NEW SIGNATURE option, and with this option ALL ESX Hosts can see the datastore, which is how you would want it, however the name of the Datastore is different.

Can somebody please advise me which is the correct and best option to choose in this type of setup?

Matthew D
Frequent Advisor

Re: ESX 4.1 & LeftHand Failover LUNS

Hi there,

Are you using multi-site or remote copy? We are using remote copy between sites at our company and for our DR tests we always select the "give new signature" option. In this case we aren't really mounting the original volume, we are mounting a snapshot of the original volume as it appeared back-in-time, and therefore we elect to give it a new signature. It's a VMFS volume that is logically independent from the original volume so vSphere shouldn't treat them as the exact same volume. My understanding is that when you select to keep the existing signature that it treats the LUN as if it was actually the original volume. But again, snapshots are copies of the original - not the original itself.

If you are using multi-site real-time replication then this doesn't apply and you probably want to keep the existing signature so that all of our ESX hosts play nice. Actually, if you are using multi-site I think you should have all your ESX hosts in the same vCenter datacenter so you wouldn't even see that dialog box to begin with.

I'm no expert so someone please correct me if I'm off base.

I hope this helps.

Re: ESX 4.1 & LeftHand Failover LUNS

Thanks for your reply.

It is using Remote Copy and yes, i suppose giving it a New Signature makes sense in a disaster.

The only thing is if the Primary site went down and you had to fail over to DR. Then after making changes, you will have to failback and i suppose you regain all your data, though you my have different Datastore Names.

Thanks again.