A virtual disk is the portion of disk space that the system has allocated to a guest. Each virtual disk is implemented as an image file with an .img extension, such as guest_A.img.

You do not explicitly create virtual disks. The vCMP^® system automatically creates a virtual disk when you set a guest to the Provisioned or Deployed state.

Using the BIG-IP^® Configuration utility or the Traffic Management Shell (tmsh), you can delete virtual disks on the system as a way to optimize disk space.

For each vCMP^® guest, the host automatically creates a sparse file to be used as a virtual disk. This amount of disk space can grow to 100 GB, and is not dependent on the number of cores that you configure for that guest. For example, allocating two cores to guest_A provides the same amount of available disk space for the guest as allocating four cores to the guest.

Note that you cannot explicitly create virtual disks; instead, the BIG-IP^® system automatically creates virtual disks when the guest changes to a Provisioned or Deployed date. You can create a guest that remains in the Configured state, but in this case, the guest has no virtual disk allocated to it.

A virtual disk is in the form of an image that resides in the /shared/vmdisks directory on each physical disk. The default file name that the BIG-IP^® system initially assigns to a virtual disk is the guest name plus a .img extension (for example, guestA.img). Using the BIG-IP Configuration utility or the Traffic Management Shell (ttmsh), you identify and manage virtual disks on the system using these file names.

If you need to create multiple guests, you most likely want to minimize the time that the vCMP^® system needs to create all of the virtual disks. The vCMP system automatically accomplishes this through a feature known as virtual disk templates. A virtual disk template is a virtual disk image that contains a fresh installation of an initial ISO image. Its purpose is to minimize the time that the system uses to create virtual disks on the system.

When you provision a guest on the system, the system creates a template for that ISO image. Later, when you create other guests that use the same ISO image, the system instantiates a copy of the virtual disk template to more rapidly create the virtual disks for those guests. The vCMP system creates a separate virtual disk template for each initial image that you initially configure for a guest.

No user intervention is required to use this feature. On the vCMP system, you can view a list of the system-created templates, or you can delete a template, but you cannot explicitly create or modify a template.

When a vCMP^® guest has no virtual disk and moves from the Configured state to the Provisioned state, the system creates a virtual disk and attaches the disk to the guest. This attachment ensures that only that guest can use the virtual disk. A guest can have only one virtual disk attached to it at any one time.

A virtual disk can become unattached from a guest when you perform one of these actions:

• Delete a guest.
• Change the Virtual Disk property of the guest to None. Note that to perform this action, you must first change the guest state to Configured.

With either of these actions, the system retains the virtual disks on the system for future use.

You can attach an existing, unattached virtual disk to a new guest that you create. Attaching an existing virtual disk to a newly-created guest saves the BIG-IP^® system from having to create a new virtual disk for the guest.

1. On the Main tab, click vCMP > Virtual Disk List .
2. Locate the Virtual Disk List area of the screen.
3. In the Name column, locate the name of the virtual disk that you want to delete.
4. To the left of the virtual disk name, select the check box.
5. Click Delete.
   The system prompts you to confirm the delete action.
6. Click Delete.

1. Use a browser and the management IP address of the vCMP host to log in to the vCMP host (hypervisor) and access the BIG-IP Configuration utility.
2. On the Main tab, click System > Disk Management .
   The display shows the logical disks and application volumes from the perspective of the vCMP host.
3. Click the logical disk for which you want to reserve disk space.
   An example of a logical disk is HD1.
4. On the menu bar, click Image List if displayed.
   The screen displays a list of the installed images on the system.
5. If a list of images appears, locate the relevant image, and in the Disk column, click the logical disk name.
6. In the Contained Application Volumes area of the screen, to the left of the list of application volume names, select the box for the vCMP application volume (named vmdisks), as well as the associated MySQL volume in that same software volume.
   Important: Be careful not to delete MySQL application volumes pertaining to other software volumes.
7. Click Delete.