3 Replies Latest reply on Nov 26, 2014 12:32 PM by jasomill1

    ghettoVCB creates entire size of thin provision disk on destination

    ctat Lurker

      Hi, I'm trying to backup a stopped VM @ ESXi 5.5 that has just been created. The harddisk capacity settings has been set to 1,5TB and thin provision.

      When I run ghettoVCB it creates a file with size of 1.5TB on the destination NFS

       

      Is there anything I'm missing?

        • 1. Re: ghettoVCB creates entire size of thin provision disk on destination
          Joolee Lurker

          That's the behaviour of the vmkfstools tool of VMWarethat GhettoVCBis using to create the clone. You can run 'vmkfstools --punchzero disk.vmdk' afterwards but it would be nice if this was a build in option in GhettoVCB just like the compression option.

          • 2. Re: ghettoVCB creates entire size of thin provision disk on destination
            Indreshkumar Lurker

            Does anyone got fix for it?

             

            I got the script working for me, backup and restore both are working.

             

            But the backup creates entire size of thin VM on destination datastore.

            • 3. Re: ghettoVCB creates entire size of thin provision disk on destination
              jasomill1 Lurker

              As I understand it, when writing to VMDKs over NFS, ghettoVCB — and, more generally, ESXi — only writes to non-zero blocks in the destination file; some NFS servers allocate space on the target filesystem for the unwritten blocks, while others do not.


              When investigating NFS server options, the key term you need to look for is "sparse file" support, and note that the NFS server software and the underlying filesystem it serves must both support sparse files to enable "thin" backups with ghettoVCB.


              Also, be aware that, even on systems that support sparse files, the file size reported in directory listings for a sparse file typically reflects the "full" size, including unwritten blocks, rather than the actual amount of disk space used. On UNIX-like systems, the du command typically reports the actual disk space used.