Copy offload

Offloaded data transfer (ODX) is a feature in Microsoft Windows Server 2012. ODX function frees up hosts and speeds the copy process by offloading the entire orchestration to a storage array.

For virtual machine (VM) operations and large data transfers, Microsoft ODX offloads the heavy lifting of data movement to the host storage array instead of doing normal read and write operations. Examples include copy operations such as:
  • VM creation
  • VM migration
  • VM cloning
  • Microsoft Windows Virtual Hard Disk (VHD) creation
  • VHD conversion
  • VM backup and recovery
  • File copy

ODX is most relevant in a Hyper-V environment for VM heavy lifting operations. Standard buffered copy is run by reading the data from the storage controller into the host, buffering it, and then writing it to another volume. The ODX function frees up hosts and speeds the copy process by offloading the entire orchestration to a storage array. This offloading is done by using tokenization for read operations and write operations, and it avoids buffering, which can ultimately cut down on processor cycles.

To enable the copy offload function, you must install the package Microsoft Multi-path I/O (MPIO) feature.
Note: MPIO features comes along with Windows OS and does not require any separate installation.
ODX is disabled by default so that you can enable the MPIO feature. After enabling the MPIO feature, you can enable the ODX by entering the chsystem -odx on CLI command.