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I have a bit of a tricky question. We are running Vsphere and our esx servers are connected to an IBM Ds4500 fibre SAN which has 8 enclosures.

We have a virtual centre with 2 data centres. One datacentre setup for our esx servers in site1 and a second datacentre setup for our esx servers in site2. Each datacentre has its own cluster setup as well. Both sites have their esx servers connected to their own IBM ds4500 fibre SAN.

In site 2 we want to move some enclosures from our IBM SAN which has datastores stored with VM's to site 1and connect these enclosures to the IBM fibre SAN in site 1. So we want to connect the site 2 enclosures to site 1 and connect these enclosures to the esx servers in site 1 and get the VM's running on these enclosures on site 1 esx servers.

My question can we get the datastores picked up the esx servers in site 1. Normally when you add datastores to esx servers it formats the datastores. But I dont want to lose the data. Is there a procedure I can follow to get this working.

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ESX will not format any datastore blindly under any normal circumstance - even during installation if it detects a recognizable VMFS partition on a volume it wont damage it unless you force it to. When discovering newly added storage no partitioning\formatting is carried out until you actively decide to create new volumes. The conditions where ESX might destroy data do not apply to what you are trying to do.

In this case since what you are going to do is physically move the underlying storage and present these existing volumes to the ESX hosts in Site 1 all you will need to do (once you've dealt with the physical storage moving bits) is to rescan the HBA's on all the ESX hosts in Site 1 to discover the "new" LUNs and the VMFS datastores on them. At that point all of the VM files in those volumes will be visible in the DataStore browser or from the Service Console and you can import any VM's that you wish to register and power up on Site 1.

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You'll of course need to physically move the enclosures to the other SAN and have it recognize the LUNs defined there; I'll assume you already have this part covered.

You'll then need to present those new LUNs to the ESX server(s) and have them do a rescan of the storage adapter(s) connecting them to the SAN; they'll automatically find the VMFS volumes existing there. No automated formatting will occur.

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