djenn40
Contributor
Contributor

Possible to Migrate Server w/ Mapping to Raw Storage?

We just set up a test server w/ one of it's hard drives mapped to raw storage. I was trying to test vmotion earlier today but when I did I got an error stating:

Unable to migrate from ESX-01 to ESX2: Virtual disk 'Hard Disk 2' is a mapped direct-access LUN that is not accessible.

I know that the ESX servers can see the storage if I scan the adapters, just wasn't sure if I need to define the storage on the actual ESX servers themselvs in order for me to able to migrate from one to the other.

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djenn40
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Contributor

Is this not possible to do? Seems like this should be achievable but I can't seem to find any information as to a setting that I can use that make this work. I thought about setting a preferred path to the LUN and then use the other servers hba's as the secondary, but all the paths to the LUN are enabled w/ the remaining 3 in a standby state.

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BryanMcC
Expert
Expert

Just make sure that you have scanned the adapters and the destination host sees the LUN that your RDM file points to.. And also can view the LUN that the RDM file resides on.

I do this all day long (maybe exagerated)...

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djenn40
Contributor
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Thanks for the tip. Both ESX hosts can see the LUN, had scanned the adapters prior to allocating it the hard disk on the VM.

?: When you saw view the LUN do you mean through the VI client? Do I need to add the LUN as storage on each host in order for it to work? We were under the impression we could just make sure the hosts saw the storage through their respective HBA's and then map the storage as raw on the individual hosts w/o doing any kind of formatting w/ the ESX hosts. Is that not accurate?

What we have is a fileserver w/ 2 hard disk that currently is on host 1. Hard disk 1 resides on a LUN that has been added to both ESX hosts. Hard disk 2 was added and points to raw storage of 150 GBs, 30 of which has been formatted through the host operating system of the fileserver. We would like to be able to migrate the fileserver from host 1 to host 2 through Vmotion but that is failing. I just logged in and tried shutting down the server and then migrating (although this totally defects our purpose). When I do that I get:

Virtual disk 'Hard Disk 2' is a mapped direct-access LUN that is not accessible.

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BryanMcC
Expert
Expert

That is accurate... I would make sure you have it listed under the storage adapter link in Configuration. You should be able to see it under both servers at least on the active HBA port on both.

And yes you are correct. You do not want to have the RDM added as storage but you have to keep in mind that the RDM pointer file is housed on a LUN that also needs to be seen by both hosts and this one must be VMFS storage..

So to sum it up...

You need two LUNs..

One with the RDM pointer file.. By default this is stored with the VM unless you specified another datastore. And this LUN must be visible by both hosts as a VMFS datastore.

Second the LUN you need the LUN you are using for the RDM. This must also be viewable/masked to both hosts but not added as a Datastore or formatted with VMFS for that matter.

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djenn40
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Ok. That makes total sense. Is there a way to find out where the RDM pointer file is stored? Checking the settings on the second hard disk it looks as though the datastore mapping file is on the same LUN as the actual server, which both ESX hosts can see. The actual RDM is on another LUN I find under both hosts on the Configuration Tab under Storage Adapters. Is there something I'm missing?

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