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  • 1.  VMFS block size question

    Posted Jun 06, 2010 03:16 PM

    Is there any reason to not go with a 8MB block size in vSphere 4? We found that with large RDM's when we snapshot we now require the VMFS to have a block size to support a delta file to the size of the RDM (even though it doesn't have the disk to expand that high).

    So the question - why not make all our VMFS luns 8MB to accomodate a 2TB lun (Raw or to allow expanding to 2TB), even though our VMFS are typically 500GB...

    thoughts? opinions?

    VMware Rocks!

  • 2.  RE: VMFS block size question

    Posted Jun 06, 2010 03:42 PM

    Here's a good blog worth checking out

    With that said, whether right or wrong, we present 600GB VMFS Luns and only use 2MB block sizes

  • 3.  RE: VMFS block size question

    Posted Jun 06, 2010 04:00 PM

    As written, there isn't a simple answer...

    There is also this site:


    Also consider that if you expand a VMFS (although I usally prefer to create new datastore instead of increase existing one) the block size is taken from the existing datastore (so, in this case could be better have always the large block).