Offloaded Data Transfer (ODX), also known as copy offload, enables direct data transfers within or between compatible storage devices without transferring the data through the host computer. ONTAP ODX copy offload provides you with performance benefits when performing copy operations on your application server over SMB installation.

In non-ODX file transfers, the data is read from the source CIFS server and is transferred across the network to the client computer. The client computer transfers the data back over the network to the destination CIFS server. In summary, the client computer reads the data from the source and writes it to the destination. With ODX file transfers, data is copied directly from the source to the destination.

Because ODX offloaded copies are performed directly between the source and destination storage, there are significant performance benefits. The performance benefits realized include faster copy time between source and destination, reduced resource utilization (CPU, memory) on the client, and reduced network I/O bandwidth utilization.

ONTAP ODX copy offload is supported on both SAN LUNs and SMB 3.0 continuously available connections.

The following use cases support using ODX copies and moves:

Intra-volume

The source and destination files or LUNs are within the same volume.
Inter-volume, same node, same storage virtual machine (SVM)

The source and destination files or LUNs are on different volumes that are located on the same node. The data is owned by the same SVM.
Inter-volume, different nodes, same SVM

The source and destination files or LUNs are on different volumes that are located on different nodes. The data is owned by the same SVM.
Inter-SVM, same node

The source and destination file or LUNs are on different volumes that are located on the same node. The data is owned by different SVMs.
Inter-SVM, different nodes

The source and destination file or LUNs are on different volumes that are located on different nodes. The data is owned by different SVMs.

Specific use cases for ODX copy offload with Hyper-V solutions include the following:

You can use ODX copy offload pass-through with Hyper-V to copy data within or across virtual hard disk (VHD) files or to copy data between mapped SMB shares and connected iSCSI LUNs within the same cluster.

This allows copies from guest operating systems to pass through to the underlying storage.
When creating fixed-sized VHDs, ODX is used for initializing the disk with zeros, using a well-known zeroed token.
ODX copy offload is used for virtual machine storage migration if the source and destination storage is on the same cluster.

To take advantage of the use cases for ODX copy offload pass-through with Hyper-V, the guest operating system must support ODX and the guest operating system’s disks must be SCSI disks backed by storage (either SMB or SAN) that supports ODX. IDE disks on the guest operating system do not support ODX pass-through.

Specific use cases for ODX copy offload with SQL Server solutions include the following:

You can use ODX copy offload to export and import SQL Server databases between mapped SMB shares or between SMB shares and connected iSCSI LUNs within the same cluster.
ODX copy offload is used for database exports and imports if the source and destination storage is on the same cluster.

ONTAP 9 Manuals ( CA08871-402 )

How ODX copy offload is used with Hyper-V and SQL Server over SMB shares

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