DELL MD3220 User Manual

Configuration: Premium Feature—Snapshot Virtual Disks

Using the simple path, you can specify:

• Snapshot Virtual Disk Name—A user-specified name that helps you 

associate the snapshot virtual disk to its corresponding snapshot repository 

virtual disk and source virtual disk. 

• Snapshot Repository Virtual Disk Name—A user-specified name that 

helps you associate the snapshot repository virtual disk to its corresponding 

snapshot virtual disk and source virtual disk. 

• Snapshot Repository Virtual Disk Capacity—The snapshot repository 

virtual disk capacity is expressed as a percentage of the source virtual disk 

capacity. The maximum percentage allowed is 120 percent.

Using the simple path, the following defaults are used for the other 

parameters of a snapshot virtual disk:

• Capacity Allocation—The snapshot repository virtual disk is created using 

free capacity on the same disk group where the source virtual disk resides. 

• Host-to-Virtual Disk Mapping—The default setting is 

Map now. 

• Percent Full—When the snapshot repository virtual disk reaches the 

specified repository full percentage level, the event is logged in the Major 

Event Log (MEL). The default snapshot repository full percentage level is 

50 percent of the source virtual disk. 

• Snapshot Repository Virtual Disk Full Conditions—When the snapshot 

repository virtual disk becomes full, you are given a choice of failing write 

activity to the source virtual disk or failing the snapshot virtual disk. 

Before using the Snapshot Virtual Disks Premium Feature in a Microsoft® 

Windows® clustered configuration, you must first map the snapshot virtual disk to 

the cluster node that owns the source virtual disk. This ensures that the cluster 

nodes correctly recognize the snapshot virtual disk.

Mapping the snapshot virtual disk to the node that does not own the source 

virtual disk before the Snapshot enabling process is completed can result in the 

operating system mis-identifying the snapshot virtual disk. This, in turn, can result in 

data loss on the source virtual disk or an inaccessible snapshot.

book.book  Page 137  Monday, June 21, 2010  11:00 AM