Dell MD3200, MD3220 owner manual Types of Virtual Disk Copies, Offline Copy, 164

Reasons to use virtual disk copy include:

•Copying data for improved access—As your storage requirements for a virtual disk change, you can use a virtual disk copy to copy data to a virtual disk in a disk group that uses drives with larger capacity within the same storage array. Copying data for larger access capacity enables you to move data to greater capacity physical disks (for example, 61 GB to 146 GB).

•Restoring snapshot virtual disk data to the source virtual disk—The Virtual Disk Copy feature enables you first to restore the data from a snapshot virtual disk and then to copy the data from the snapshot virtual disk to the original source virtual disk.

•Creating a backup copy—The Virtual Disk Copy feature enables you to create a backup of a virtual disk by copying data from one virtual disk (the source virtual disk) to another virtual disk (the target virtual disk) in the same storage array, minimizing the time that the source virtual disk is unavailable to host write activity. You can then use the target virtual disk as a backup for the source virtual disk, as a resource for system testing, or to copy data to another device, such as a tape drive or other media.

NOTE: Recovering from a backup copy — You can use the Edit Host-to-Virtual Disk Mappings feature to recover data from the backup virtual disk you created in the previous procedure. The Mappings option enables you to unmap the source virtual disk from its host and then to map the backup virtual disk to the same host.

Types of Virtual Disk Copies

You can perform either offline or online virtual disk copies. To ensure data integrity, all I/O to the target virtual disk is suspended during either type of virtual disk copy operation. After the virtual disk copy is complete, the target virtual disk automatically becomes read-only to the hosts.

Offline Copy

An offline copy reads data from the source virtual disk and copies it to a target virtual disk, while suspending all updates to the source virtual disk when the copy is in progress. In an offline virtual disk copy, the relationship is between a source virtual disk and a target virtual disk. Source virtual disks that are participating in an offline copy are available for read requests, while the virtual disk copy displays the In Progress or Pending status. Write requests are allowed only after the offline copy is complete. If the source virtual disk is

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Configuration: Premium Feature—Virtual Disk Copy