Mapping the snapshot virtual disk to the node that does not own the source virtual disk before the snapshot enablingprocess is completed can result in the operating system misidentifying the snapshot virtual disk. This can result in dataloss or an inaccessible snapshot.Virtual Disk CopyVirtual disk copy is a premium feature you can use to:• Back up data.• Copy data from disk groups that use smaller-capacity physical disks to disk groups using greater capacityphysical disks.• Restore snapshot virtual disk data to the source virtual disk.Virtual disk copy generates a full copy of data from the source virtual disk to the target virtual disk in a storage array.• Source virtual disk — When you create a virtual disk copy, a copy pair consisting of a source virtual disk and atarget virtual disk is created on the same storage array. When a virtual disk copy is started, data from the sourcevirtual disk is copied completely to the target virtual disk.• Target virtual disk — When you start a virtual disk copy, the target virtual disk maintains a copy of the data fromthe source virtual disk. You can choose whether to use an existing virtual disk or create a new virtual disk as thetarget virtual disk. If you choose an existing virtual disk as the target, all data on the target is overwritten. Atarget virtual disk can be a standard virtual disk or the source virtual disk of a failed or disabled snapshot virtualdisk.NOTE: The target virtual disk capacity must be equal to or greater than the source virtual disk capacity.When you begin the disk copy process, you must define the rate at which the copy is completed. Giving the copyprocess top priority slightly impacts I/O performance, while giving it lowest priority makes the copy processlonger to complete. You can modify the copy priority while the disk copy is in progress. For more information,see the online help.Virtual Disk RecoveryYou can use the Edit host server-to-virtual disk mappings feature to recover data from the backup virtual disk. Thisfunctionality enables you to unmap the original source virtual disk from its host server, then map the backup virtual diskto the same host server.Ensure that you record the LUN used to provide access to the source virtual disk. You need this information when youdefine a host server-to-virtual disk mapping for the target (backup) virtual disk. Also, be sure to stop all I/O activity to thesource virtual disk before beginning the virtual disk recovery procedure.Using Snapshot And Disk Copy TogetherYou can use the Snapshot Virtual Disk and Virtual Disk Copy premium features together to back up data on the samestorage array, or to restore the data on the snapshot virtual disk to its original source virtual disk.You can copy data from a virtual disk in one of the two ways:• By taking a point-in-time snapshot of the data• By copying the data to another virtual disk using a virtual disk copyYou can select a snapshot virtual disk as the source virtual disk for a virtual disk copy. This configuration is one of thebest ways you can apply the snapshot virtual disk feature, since it enables complete backups without any impact to thestorage array I/O.27
