vSphere Storage Appliance

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  • 1.  P2V server with large SAN LUN Attached

    Posted Jun 30, 2010 03:05 PM

    So I have a Windows 2003 server that is mapped to a 6.5TB lun on our SAN. I need to virtualize the server. I can perform a P2V on its system drive (80GB local drive) and boot the virtual server created, however I need to map its LUN as well since the server is a file server that is actively used. RDM doesn't work since the storage the guest is on doesn't support drives over 2TB. The SAN doesn't support iSCSI connections so I can't map it that way. I believe I am SOL but before I break that news to my boss I wanted to be sure I've exhausted all possibilites. I've looked into NPIV but I don't think that will work, same for paravirtualization.

    I'm pretty much screwed right?



  • 2.  RE: P2V server with large SAN LUN Attached

    Posted Jun 30, 2010 03:14 PM

    Is the entire 6.5 TB being utilized at the moment? You could break it down into multiple 2 TB drives and just perform a file migration. Why will NPIV not work?






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  • 3.  RE: P2V server with large SAN LUN Attached

    Posted Jun 30, 2010 03:19 PM

    The lun is about 80% utilized. It is partitioned at the windows level into a 4TB and 2.5TB partition. I can't easily destroy the LUN and recreate as 3+ 2tb LUNs unfortunatly. It would require an extended outage that would be a major issue.

    Maybe I can use NPIV, from what I found it appeared however that the RDM will still be managed by vsphere (creating an vmdk file on the datastore) and that is where my issue is since I can't create storage over 2TB since the datastore is limited to 8mb blocks and 2tb vmdks. If that is not correct I would be one happy camper.



  • 4.  RE: P2V server with large SAN LUN Attached

    Posted Jun 30, 2010 03:23 PM

    Yeah, it looks like you are correct and that a RDM will still be stored under VMFS.

    http://www.brocade.com/downloads/documents/white_papers/white_papers_partners/NPIV_ESX4_0_GA-TB-145-01.pdf






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  • 5.  RE: P2V server with large SAN LUN Attached

    Posted Jun 30, 2010 05:08 PM

    NPIV and RDMs are different. I don't know anything about NPIV, but I would use an RDM for this. As I understand it, the RDM is two pieces: a file that gets stored with the VM on the VMFS filesystem, and then the LUN that gets attached directly to the VM. The file with the VM is very small -- just points the VM to the LUN. Since that LUN is not running VMFS, it can be whatever size you need (not limited by VMFS sizing restrictions). You should be able to take the current LUN, zone it to the host "as is", and then attach that LUN as an RDM.

    Here's the basic process: Zone the existing 6.5 TB LUN to the host(s). Rescan. Go to the VM and add a new Disk, making sure to choose the RDM as the type of disk to add.

    It has been a long time since I played w/ RDMs, but this is a case where it seems to solve your problem.

    Another possible solution: Create 4 2-TB LUNs, and then use them as extents to add size to the VMFS, so you end up with an 8TB Datastore (4x2TB). Then you should be able to create a disk of the size you need and move the data over. Again, I haven't played with any disks this size, but that seems like it would work, too.



  • 6.  RE: P2V server with large SAN LUN Attached

    Posted Jun 30, 2010 05:13 PM

    Yea that was my first attempt, zoning the LUN to be accessed as an RDM by my ESX servers. However, RDM drives also require a vmdk-disk file that has to reside on a current datastore, and apparantly it follows the same limitations as vmdks in regards to sizing. So it doesn't appear possible to attach via RDM, a LUN greater that 2TB to a VM. I was hoping there was some super secret method of mapping the LUN directly to the guest in a similar method to iSCSI but with fibre.



  • 7.  RE: P2V server with large SAN LUN Attached

    Posted Jun 30, 2010 05:32 PM

    Just a thought here. Start planning to break up storage into smaller chunks. Create a new file server VM with multiple VMDKs as appropriate. Use DFS to replicate from old to new.



  • 8.  RE: P2V server with large SAN LUN Attached

    Posted Jun 30, 2010 06:01 PM

    Yea that is kind of where I am now. The downside is I need to order additional storage for my SAN, which I was trying to avoid because the SAN is being replaced in about 2 months :smileyhappy:



  • 9.  RE: P2V server with large SAN LUN Attached

    Posted Jun 30, 2010 06:08 PM

    Will you have any overlap time with the old and new SAN? Can you shrink the LUNs as you move data to a new VMDK?