Dell PowerVault MD3820f - Manual (Page 177)

Creating A Snapshot Virtual Disk Using The Advanced
Path
About The Advanced Path
Use the advanced path to choose whether to place the snapshot repository virtual disk on free capacity
or unconfigured capacity and to change the snapshot repository virtual disk parameters. You can select
the advanced path regardless of whether you use free capacity or unconfigured capacity for the snapshot
virtual disk.
Using the advanced path, you can specify the following parameters for your snapshot virtual disk:
• 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.
• Capacity Allocation — This parameter allows you to choose where to create the snapshot repository
virtual disk. You can allocate capacity by using one of the following methods:
– Use free capacity on the same disk group where the source virtual disk resides.
– Use free capacity on another disk group.
– Use unconfigured capacity and create a new disk group for the snapshot repository virtual disk.
– It is recommended placing the snapshot repository virtual disk within the disk group of the source
virtual disk. This ensures that if drives associated with the disk group are moved to another storage
array, all the virtual disks associated with the snapshot virtual disk remain in the same group.
• 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.
• Percent Full—When the snapshot repository virtual disk reaches the user-specified repository full
percentage level, the event is logged in the Major Event Log (MEL). The default snapshot repository
full percentage level is 50% of the source virtual disk.
• Snapshot Repository Virtual Disk Full Conditions — Choose whether to fail writes to the source virtual
disk or fail the snapshot virtual disk when the snapshot repository virtual disk becomes full.
• Host-to-Virtual Disk Mapping — Choose whether to map the snapshot virtual disk to a host or host
group now or to map the snapshot virtual disk later. The default setting is Map later.
Preparing Host Servers To Create The Snapshot Using The Advanced Path
• 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.
• For details on mapping the snapshot virtual disk to the secondary node, see the documentation on
storage arrays with Microsoft Windows Server Failover Clusters at dell.com/support/manuals.
The destination of a snapshot repository virtual disk is determined based on the free capacity available in
the disk group. A snapshot repository virtual disk requires a minimum of 8 MB free capacity. You can
choose your preferred creation path—simple or advanced—if the disk group of the source virtual disk has
the required amount of free space.
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