VMware Virtual Disk Manager is a utility in GSX Server that allows you to create, manage and modify virtual disk files from the command line or within scripts.

One key feature is the ability to enlarge a virtual disk so its maximum capacity is larger than it was when you created it. This way, if you find you need more disk space on a given virtual disk, but do not want to add another virtual disk or use ghosting software to transfer the data on a virtual disk to a larger virtual disk, you can simply change the maximum size of the disk. This is something you cannot do with physical hard drives.

Another feature allows you to change whether or not all virtual disk space is preallocated or growable, and whether or not the virtual disk is stored in a single file or split into 2GB files. For example, you might find that you preallocated all the disk space for a virtual disk, but need to reclaim some hard disk space on the host. You can convert the preallocated virtual disk into a growable disk and remove the original virtual disk file. The new virtual disk is large enough to contain all the data on the original virtual disk. The virtual disk grows in size as you add data to it, as if you never preallocated the disk space when you created the virtual disk.

These features and the ability to use scripting to automate management of virtual disks were not possible with VMware products until now.

You can use the virtual disk manager to:

You can use the virtual disk manager with virtual disks created under VMware GSX Server, VMware Workstation and VMware VirtualCenter (provided the virtual disk was created on a GSX Server host managed by VirtualCenter).

You cannot use the virtual disk manager to create physical (raw) disks. Physical disks cannot be shrunk, neither by the virtual disk manager nor by GSX Server.

The following sections provide more information about the virtual disk manager: