Vmkfstools

Command for directly working with the (virtual) disk at host level.

With this command you can destroy whole virtual machines if you do not take the right precautions (hint: BACKUPS) and are not familiar with the command.

Usage

vmkfstools [options] target

Whereby target can be either a physical disk, a virtual disk or a device.

The command is mostly known for using it to manipulate virtual disks. Beware that if you are working with a virtual disk that in most cases the virtual machine itself should be shut down.

Options

from the help page of the command.

OPTIONS FOR FILE SYSTEMS

vmkfstools -C --createfs [vmfs3|vmfs5]
              -b --blocksize #[mMkK]
              -S --setfsname fsName
          -Z --spanfs span-partition
          -G --growfs grown-partition
  deviceName

          -P --queryfs -h --humanreadable
          -T --upgradevmfs
  vmfsPath

OPTIONS FOR VIRTUAL DISKS

vmkfstools -c --createvirtualdisk #[gGmMkK]
              -d --diskformat [zeroedthick|
                               thin|
                               eagerzeroedthick]
              -a --adaptertype [buslogic|lsilogic|ide|
                                lsisas|pvscsi]
          -w --writezeros
          -j --inflatedisk
          -k --eagerzero
          -K --punchzero
          -U --deletevirtualdisk
          -E --renamevirtualdisk srcDisk
          -i --clonevirtualdisk srcDisk
              -d --diskformat [zeroedthick|
                               thin|
                               eagerzeroedthick|
                               rdm:<device>|rdmp:<device>|
                               2gbsparse]
          -X --extendvirtualdisk #[gGmMkK]
              [-d --diskformat eagerzeroedthick]
          -M --migratevirtualdisk
          -r --createrdm /vmfs/devices/disks/...
          -q --queryrdm
          -z --createrdmpassthru /vmfs/devices/disks/...
          -v --verbose #
          -g --geometry
          -x --fix [check|repair]
          -e --chainConsistent
  vmfsPath

OPTIONS FOR DEVICES

          -L --lock [reserve|release|lunreset|targetreset|busreset|readkeys|rea                              dresv] /vmfs/devices/disks/...
          -B --breaklock /vmfs/devices/disks/...

vmkfstools -H --help

Examples

Export a VM disk in 2GB chunks, note that since ESXi 5.1+ the 2GB sparse driver is disabled.

vmkfstools -i /vmfs/volumes/storagename/YourVM/YourVM.vmdk -d 2gbsparse /vmfs/volumes/storage2/YourVM/YourVM.vmdk

-x, --fix -[check|repair]

This option will check and/or repair the virtual disk in case of an unclean shutdown.

Example:

vmkfstools --fix check /vmfs/volumes/esx4-1-local-storage-1/dummy/dummy.vmdk
Disk is error free

-J, --miscop [setuuid | getuuid]

'setuuid´ option creates a unique identifier (UUID) for the virtual disk and stores the UUID in the descriptor file of the

virtual disk. If the descriptor file already contains a UUID, it will be overwritten with a new one. 

Please make sure that the virtual disk does not have a UUID before using this option.

´getuuid´ option displays the UUID of the virtual disk.

dumpfs can be used by specifying either "-D | --dumpfs" and specifying a VMFS volume, file or folder.

Example:

# vmkfstools -D /vmfs/volumes/esx4-1-local-storage-1/

Lock [type 10c00001 offset 4292608 v 33, hb offset 3440640
gen 11, mode 0, owner 00000000-00000000-0000-000000000000 mtime 2509]
Addr <4, 0, 0>, gen 1, links 4, type dir, flags 0, uid 0, gid 0, mode 1755
len 1260, nb 1 tbz 0, cow 0, zla 1, bs 1048576

activehosts can be used by specifying "--activehosts" and specifying a VMFS volume

Example:

# vmkfstools --activehosts /vmfs/volumes/esx4-1-local-storage-1/
Found 1 actively heartbeating hosts on volume '/vmfs/volumes/esx4-1-local-storage-1/'
(1): MAC address 00:50:56:92:3f:86

Reclaim disk space by returning unused blocks of data in the virtual disk to the host OS. This will only work if your virtual disk is of type thin.

Example:

# vmkfstools --punchzero myvm.vmdk
vmfsDisk: 1, rdmDisk: 0, blockSize: 1048576 
Hole Punching: 3% done.

Links

Some useful vmkfstools ‘hidden’ options

William also has a list here