VMware vSphere

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  • 1.  RDM mapping file size?

    Posted Oct 21, 2011 05:04 AM

    So i've i attached some LUNs to a VM that resides on a 180 gb datastore.

    One of the LUNs was 558gb in size.... and it created a mapping file and stored it with the VM on the datastore.

    When i browse the datastore it says that the there is a vmdk file of a 558gb size........... thats bigger than the actual datastore???

    Is this a mistake... or not the actual size of the mapping file vmdk? 

    Presumably its just a file indicating the size of the lun it points at....?   which makes sense because i dont get any space freed up if i delete one of the mapping file vmdk's from the datastore.

    How much space do the actual mapping files themselves take up in the datastore?

    Advice appreciated.



  • 2.  RE: RDM mapping file size?
    Best Answer

    Posted Oct 21, 2011 08:09 AM

    Using RDM with a virtual machine you will see a VMDK file just big as the LUN size on the VMFS datastore (within the vSphere client), but it is not allocated at the VMFS datastore.

    Logging in the console you will see two files when mounted with RDM;

    virtualdisk-rdmp.vmdk size 0 bytes
    virtualdisk.vmdk size 64 bytes