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RDM snapshot under VM

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  • RDM snapshot under VM

    Hello ALL,
    This forum/Website is probably one of the best resources for Vmware. I've gotten most of my vmware howto's and fixes on this site.

    My question is, if I take a snapshot under Virtual center client of a machine, that machine also has RDM lun mapping. Will VC or VM also take a snapshot of the RDM Lun? I didn't think it did since it is not VMFS, but again I could be wrong.

    Thank you in advance for your help...

    P.S I am looking forward to my VM training next week and hopefully VCP.

  • #2
    Re: RDM snapshot under VM


    are you using virtual RDMs or physical RDMs?

    if you have a physical RDM, then snapshots are disabled.

    with a vRDMS, the snapshot can encompass the entire virtual setup, so yes... kinda. as long as the vRDM was defined as "independant" then you can.

    there are other caveats as well, like having 2 virtuals sharing a vRDM will disable snapshots...

    you can convert pRDMs the vRDMs, after powering of the virtual machine... if performance isnt an issue. in an instance where performance is not an issue and you can use vRDMs, you should as it eases these problems with pRDMs.

    it can be tricky working with pRDMs if you dont take backing up into consideration prior to the deployment.

    now jason can come along and correct any errors ive made in my statements

    its easier to beg forgiveness than ask permission.
    Give karma where karma is due...


    • #3
      Re: RDM snapshot under VM

      Thanks a million for your reply!

      The mapping was done by other Tech/Engineer, that LUN is mapped directly to the SAN, so I am guessing that its a physical RDM and no snapshot.

      How can I tell within VC console how the RDM's are mapped? I can see the mapping inside the SAN utility to both ESX server LUN.

      Thank You,


      • #4
        Re: RDM snapshot under VM

        James has it covered.

        Here's the VMware technical reference that covers what you're looking for:
        Pages 143-153
        VCDX3 #34, VCDX4, VCDX5, VCAP4-DCA #14, VCAP4-DCD #35, VCAP5-DCD, VCPx4, vEXPERTx4, MCSEx3, MCSAx2, MCP, CCAx2, A+ - VMware Virtualization Evangelist
        My advice has no warranties. Follow at your own risk.


        • #5
          Re: RDM snapshot under VM

          Originally posted by jasonboche View Post
          James has it covered.
          haha! appreciate the confirmation. i was really not sure if i had that str8...

          Thanks for the reply Jason!
          its easier to beg forgiveness than ask permission.
          Give karma where karma is due...