Learning about volume copy

What a volume copy is

Volume copy is a way of copying both data in the active file system and data in snapshots from one volume to another. You can initiate a volume copy with the vol copy start command, which enables you to copy data from one volume to another volume, either to the same filer or a different filer. The result of copying a volume is a restricted volume containing the same data as the source volume at the time you initiated the copy operation.

Benefits of the vol copy command set

Although you can copy data on the filer using client programs such as cpio or use the Data ONTAP dump and restore commands, the vol copy command set offers the following benefits:

When a vol copy command reads and writes data, Data ONTAP does not traverse directories on the filer. Data is copied block for block directly from the disks, which means that Data ONTAP can finish the copying faster than it could with other methods.
Using a vol copy command, Data ONTAP preserves the snapshot data of the source volume. If, in the future, users might need to use snapshots that were taken before data was copied from one volume to another, you can use a vol copy command for migrating data. For example, if users accidentally delete files and need to recover them, they can do so from the preserved data.

When to copy volumes

The following table describes some situations where you might find copying volumes useful.

Situation	Reasons for copying one volume to another
You want to migrate data from one filer to another.	The destination filer has more storage or is a model that supports newer technology.
You want to move a volume from one set of disks to another on the same filer.	You want to Split a volume Expand filer storage Examples You can copy the vol0 volume to the vol1 volume and then delete duplicated files and directories in these volumes so that the original contents of vol0 are split into two volumes. You have six 9-GB disks for the vol0 volume and four 18-GB spare disks. You can migrate vol0 to the four 18-GB disks and replace all the 9-GB disks with larger capacity disks.
You want to copy data from one filer to another regularly to ensure high data availability.	After you copy the data, clients can switch to the destination filer in the following scenarios: When you shut down the source filer for software or hardware upgrades, or if the source filer is not available for reasons such as natural disasters, you can put the destination volume online to continue file service. If a network client process accidentally deletes a large number of files on the source filer, clients can continue to have access to the files on the destination filer while you are restoring the files to the source filer. Note This is also a good application for SnapMirror.

Situation

Reasons for copying one volume to another

You want to migrate data from one filer to another.

The destination filer has more storage or is a model that supports newer technology.

You want to move a volume from one set of disks to another on the same filer.

You want to

Split a volume
Expand filer storage

Examples

You can copy the vol0 volume to the vol1 volume and then delete duplicated files and directories in these volumes so that the original contents of vol0 are split into two volumes.

You have six 9-GB disks for the vol0 volume and four 18-GB spare disks. You can migrate vol0 to the four 18-GB disks and replace all the 9-GB disks with larger capacity disks.

You want to copy data from one filer to another regularly to ensure high data availability.

After you copy the data, clients can switch to the destination filer in the following scenarios:

When you shut down the source filer for software or hardware upgrades, or if the source filer is not available for reasons such as natural disasters, you can put the destination volume online to continue file service.
If a network client process accidentally deletes a large number of files on the source filer, clients can continue to have access to the files on the destination filer while you are restoring the files to the source filer.
Note
This is also a good application for SnapMirror.