The VM File Copy Problem
Virtualization related storage files (VHD, VMDK etc.) typically range in size from tens of GBs to hundreds of GBs. Copying such large files can tax a server bus, performance of other running VMs, as well as network performance.

Unfortunately, many of the usage scenarios for Virtual Machines directly lead to a file copy. For example:

• Checking in or checking out a file to/from SCVMM is typically a file copy operation
• Moving VMs to/from cloud is a file copy operation
• Moving VMs from a test server to a production server is a file copy operation
• Migrating from Hyper-V 1.0 based on Windows Server 2008 to Hyper-V 2.0 based on Windows Server 2008 R2 and its Clustered Shared Volumes (CSV) also leads to a file copy.

The current solution - an inefficient file copy
For non running VMs, the current file copy operations are inefficient in a number of ways:

• Data that is unused by the file system inside the VM is copied
• Data that is used by the file system inside the VM, but will never be used is copied. For example, when a master VM is checked out, the hibernation file will also be copied. The checked out VMs will typically always be booted afresh and never resumed, at least the first time the VM is fired up
• Meaningful data is copied, and then immediately overwritten. For example, the current usage requires an admin to
1. Wait for a check out file copy operation to complete
2. Boot the VM
3. Install some new software e.g. a SP or Microsoft SQL Server and this will overwrite a fair amount of the VHD file copied in step 1

Introducing VHDCopy
The VMUtil Inc. family of products work together to remove the inefficiencies. The patent pending VHDCopy refrains from copying meaningless portions of a VHD file. VHDCopy and VMProv work jointly to minimize copying data and then immediately overwriting it.