Storage Partitioning; Snapshot Virtual Disks - Dell PowerVault MD3220 Cli Manual

Storage Partitioning

Storage partitioning enables hosts to share access to virtual disks in a storage
array. You create a storage partition when you define the following storage
array assignments:
• A host
• A host group
• Virtual disk-to-logical unit number (LUN) mapping
The virtual disk-to-LUN mapping enables you to define which host group or
host has access to a particular virtual disk in the storage array.
After you create a virtual disk copy, the target virtual disk automatically
becomes read-only to hosts to ensure that the data is preserved. Hosts that
have been mapped to a target virtual disk do not have write access to the
virtual disk, and any attempt to write to the read-only target virtual disk
results in a host I/O error.
If you want hosts to have write access to the data on the target virtual disk,
use the set virtualDiskCopy command to disable the read-only attribute for
the target virtual disk.

Snapshot Virtual Disks

A snapshot virtual disk is a point-in-time image of a virtual disk. It is typically
created so that an application, such as a backup, can access the snapshot
virtual disk and read the data while the source virtual disk remains online and
accessible to hosts.
CAUTION:
Before using the source virtual disk of a snapshot virtual disk as your
target, you must disable all snapshot virtual disks associated with the source
virtual disk. By disabling the snapshot virtual disks, you avoid altering the
snapshot data if the source virtual disk is changed.
Creating a snapshot virtual disk automatically creates a snapshot repository
virtual disk. The snapshot repository virtual disk stores information about the
data that has changed since the snapshot virtual disk was created. Snapshot
repository virtual disks cannot be selected as a source virtual disk or target
virtual disk in a virtual disk copy.
The virtual disk for which the point-in-time image is created is the source
virtual disk and must be a standard virtual disk in the storage array.
Using the Virtual Disk Copy Feature
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