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vksingh's avatar
vksingh
Level 4
11 years ago

Zeroed VMDKs and Exclude Deleted Blocks in VMware policy

Can someone confirm if I enable "Exclude Deleted Blocks" in the Vmware policy type, VMs which has lazy or eager zeroed thick disks will not backup free space?

  • Tested it and know it for sure now that free FILESYSTEM space will NOT be backed up even on lazy or eager zeroed thick disks if "exclude delete blocks" have been enabled

6 Replies

  • yes, it will not backup the free space..

    but if you enable this option  you would not be able to do the file recovery from the VM backups.

    see below from netbackup Vmware admin guide

    Enable file recovery fromVMbackup
    This option allows restore of individual files from the backup. With or without this option,
    you can restore the entire virtual machine.
    You can also use this option for incremental backups: in the policy schedule, select
    differential incremental backup or cumulative incremental backup.
    To perform a VMware backup to a deduplication storage unit, select this option. This
    option provides the best deduplication rates.
    To back up a virtual machine that contains Veritas Storage Foundation Volume Manager
    volumes, disable this option. Also make sure that the Exclude deleted blocks option is
    disabled.

     

    Exclude deleted blocks

    Reduces the size of the backup image by excluding any unused or deleted blocks within
    the file system on the virtual machine. This option supports the following file systems:
    Windows NTFS, and Linux ext2, ext3, and ext4.
    This option uses proprietary mapping technology to identify vacant sectors (allocated
    but empty) within the file system.
    See “About reducing the size of VMware backups” on page 109.
    To back up a virtual machine that contains Veritas Storage Foundation Volume Manager
    volumes, disable this option. Also make sure that the Enable file recovery fromVM
    backup option is disabled.
  • That has got me worried. Where does it say that if you enabled "Exclude Deleted Blocks" you cannot do file level recovery?

  • To back up a virtual machine that contains Veritas Storage Foundation Volume Manager
    volumes, disable this option. Also make sure that the Exclude deleted blocks option is
    disabled.
     
    may be it is limitted only to the VMs contains Veritas Storage Foundation Volume Manager Volumes , worth testing in and let us know ..  :-)
  • Thats is ok. This is only for Veritas Vol Mgr Vols.

    I will be testing in next couple of weeks and will post the results. I have read the documents before and know deleted block will be excluded if I enable this option. Question was about how eager zero filled disks in VMs behave.

    As zero filling a disk does not allocation the blocks to File System I am expecting zero filling will not change the behaviour. Was looking for confirmation if anyone has already tested.  

  • Tested it and know it for sure now that free FILESYSTEM space will NOT be backed up even on lazy or eager zeroed thick disks if "exclude delete blocks" have been enabled