Manage Virtual Disks

Virtual machine disks are listed by vss-cli compute vm get <name-or-vm-id> disk <unit> and updated, removed and created by vss-cli compute vm set <name-or-vm-id> disk <unit>. This tutorial walks you through the process of managing virtual machine disks.

List

To list a summary of current virtual machine disks, use vss-cli compute vm get <name-or-vm-id> disk or vss-cli compute vm get <name-or-vm-id> disk <unit> to get specific information of a disk unit. For instance, the following virtual machine has two virtual disks configured:

vss-cli compute vm get VMName disk

label          unit  controller.virtual_device_node
-----------  ------  --------------------------------
Hard disk 1       1  SCSI controller 0:0
Hard disk 2       2  SCSI controller 1:1
Hard disk 3       3  SCSI controller 1:0

Getting specific information of a given disk unit, run vss-cli compute vm get <name-or-vm-id> disk <unit> as follows:

vss-cli compute vm get vm-1233 disk 1

label               : Hard disk 1
unit                : 1
virtual_device_node : SCSI controller 0:0
capacity_gb         : 8
shares.level        : normal

Getting backing information of a particular disk is available by including the sub-command backing in the disk command:

vss-cli compute vm get vm-1233 disk 1 backing

descriptor_file_name: None
device_name         : None
disk_mode           : persistent
file_name           : [CL-NSTOR47-NFS-vol33] 1806P-modest_davinci_66/1806P-modest_davinci_66.vmdk
lun_uuid            : None
thin_provisioned    : True

Getting details of the SCSI controller of a particular disk is available by including the sub-command scsi in the disk command:

vss-cli compute vm get vm-1233 disk 1 scsi

bus_number          : 0
label               : SCSI controller 0
type                : VirtualLsiLogicController

Update

There are three allowed actions to modify a given disk unit: remove, update and create as shown by vss-cli compute vm set <name-or-vm-id> disk mk|up|rm --help command:

Usage: vss-cli compute vm set disk [OPTIONS] COMMAND [ARGS]...

  Manage virtual machine disks. Add, expand and remove virtual disks.

Options:
  --help  Show this message and exit.

Commands:
  mk  Create new disk
  rm  Remove disk from vm
  up  Update disk capacity and controller

Expand

In order to expand an existing disk, use vss-cli compute vm set <name-or-vm-id> disk up <unit> -c <capacityGB> as shown below:

vss-cli compute vm set vm-1234 disk up 1 --capacity 50

Controller

SCSI controllers are also available to update via the CLI. Use vss-cli compute vm set <name-or-vm-id> disk up <unit> -s <bus_number> as follows:

vss-cli compute vm set vm-1234 disk up 1 --scsi 1

Backing Mode

Disk backing modes can be updated via vss-cli compute vm set <name-or-vm-id> disk up <unit> -m <disk-mode>:

vss-cli compute vm set vm-1234 disk up 1 --backing-mode independent_persistent

Refer to the following table to pick the right backing mode:

Name	Description

Name	Description
append	Changes are appended to the redo log; you revoke changes by removing the undo log.
independent_nonpersistent	Same as nonpersistent, but not affected by snapshots.
independent_persistent	Same as persistent, but not affected by snapshots.
nonpersistent	Changes to virtual disk are made to a redo log and discarded at power off.
persistent	Changes are immediately and permanently written to the virtual disk.
undoable	Changes are made to a redo log, but you are given the option to commit or undo.

Backing Sharing Mode

Disk backing sharing modes can be updated via vss-cli compute vm set <name-or-vm-id> disk up <unit> -r <sharing>:

Refer to the following table to pick the right backing sharing:

Name	Description

Name	Description
sharingmultiwriter	The virtual disk is shared between multiple virtual machines.
sharingnone	The virtual disk is not shared.

Create

Creating a new virtual machine disk is as simple as updating, but switching the sub-command to mk, for example:

vss-cli compute vm set vm-1233 disk mk --disk 20

Also, it supports providing both backing_mode and backing_sharing in the following format <capacity_gb>=<backing_mode>=<backing_sharing>=<backing_vmdk>. If no backing_mode and backing_sharing and backing_vmdk are provided, defaults are:

backing_mode: persistent
backing_sharing: sharingnone
backing_vmdk: automatically generated by vSphere. (advanced)

For instance:

vss-cli compute vm set vm-1233 disk mk --disk 100 --disk 100=independent_persistent

Or in particular use cases, there could be a need for a sharingmultiwriter sharing mode:

vss-cli compute vm set vm-1233 disk mk --disk 100=persistent=sharingmultiwriter

The --disk payload can also be provided in JSON format:

vss-cli compute vm set vm-1233 disk mk –disk 100 –disk ‘{“capacity_gb”: 100, “backing_mode”: “independent_persistent”}’

Specify SCSI controller

By default, the ITS Private Cloud API creates disks using the first SCSI controller and available slots in it. If a SCSI controller is full, a new controller will be created using our pre-defined settings based on operating systems.