Dell PowerVault MD3000 - Manual (Page 61)

Using the Snapshot Feature
61
Using the Snapshot Feature
This chapter describes how the Snapshot feature works, lists the snapshot
script commands, and explains how to use the commands to create snapshot
virtual disks. Additional information about the Snapshot feature and related
definitions is available in the online help, the Installation Guide, the MD
Storage Manager User’s Guide, and the Owner’s Manual.
The Snapshot feature creates a snapshot virtual disk that you can use as a
backup of your data. A snapshot virtual disk is a logical point-in-time image of
a standard virtual disk. Because it is not a physical copy, a snapshot virtual
disk is created more quickly than a physical copy and requires less physical
disk space. Typically, you create a snapshot virtual disk so that an application,
such as a backup application, can access the snapshot virtual disk. The
application reads the data while the source virtual disk remains online and
user accessible. You can also create several snapshot virtual disks of a source
virtual disk and write data to the snapshot virtual disks to perform testing and
analysis.
NOTE:
If you ordered Premium Features for the Snapshot Virtual Disks, you
received a Premium Features Activation card shipped in the same box as your Dell
PowerVault
™ MD storage array. Follow the directions on the card to obtain a key
file and to enable the feature. For more information, see "Premium Feature —
Snapshot Virtual Disks" in the User’s Guide.
Snapshot virtual disks allow you to perform the following tasks:
• Create a complete image of the data on a source virtual disk at a particular
point in time.
• Use only a small amount of disk space.
• Provide quick, frequent, nondisruptive backups; or test new versions of a
database system without affecting actual data.
• Provide for snapshot virtual disks to be read, written, and copied.
• Use the same availability characteristics of the source virtual disk (such as
redundant array of independent disks (RAID) protection and redundant
path failover).