Dell PowerVault MD3000 Hardware Owner's Manual

Also see for PowerVault MD3000: Support Matrix Brochure Information update Configuration Information update

Contents

Dell PowerVault MD3000 Hardware Owner's Manual Manual pdf 39 page image

Using Your RAID Enclosure 39Snapshot Repository Virtual DiskWhen you create a snapshot virtual disk, it automatically creates a snapshot repository virtual disk. Asnapshot repository is a virtual disk created in the storage array as a resource for a snapshot virtual disk. Asnapshot repository virtual disk contains snapshot virtual disk metadata and copy-on-write data for aparticular snapshot virtual disk. The repository supports one snapshot only.Because the only data physically stored in the snapshot repository virtual disk is that which has changedsince the time of the snapshot, the snapshot technology uses less disk space than a full physical copy.You cannot select a snapshot repository virtual disk as a source virtual disk or as a target virtual disk in avirtual disk copy. If you select a Snapshot source virtual disk as the target virtual disk of a virtual diskcopy, you must disable all snapshot virtual disks associated with the source virtual disk.Virtual Disk CopyVirtual Disk Copy is a premium feature you can use to back up data, copy data from disk groups that usesmaller-capacity physical disks to disk groups using greater capacity physical disks, or restore snapshotvirtual disk data to the source virtual disk. Virtual Disk Copy generates a full copy of data from thesource 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 diskand a target virtual disk is created on the same storage array. When a virtual disk copy is started, datafrom the source virtual 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 thedata from the source virtual disk. You can choose whether to use an existing virtual disk or create a newvirtual disk as the target virtual disk. If you choose an existing virtual disk as the target, all data on thetarget is overwritten. A target virtual disk can be a standard virtual disk or the source virtual disk of afailed or disabled snapshot virtual disk.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. Givingthe copy process top priority will slightly impact I/O performance, while giving it lowest priority willmake the copy process take longer to complete. You can modify the copy priority while the disk copy is inprogress.You can find more details on using the virtual disk copy feature in the MD Storage Manager User’s Guide.Virtual Disk RecoveryYou can use the Edit host-to-virtual disk mappings feature to recover data from the backup virtual disk.This functionality enables you to unmap the original source virtual disk from its host, then map thebackup virtual disk to the same host.Ensure that you record the LUN used to provide access to the source virtual disk. You will need thisinformation when you define a host-to-virtual disk mapping for the target (backup) virtual disk. Also, besure to stop all I/O activity to the source virtual disk before beginning the virtual disk recovery procedure.