Dell PowerVault MD3820f - Manual (Page 175)

• Snapshot schedules can be created when the snapshot virtual disk is initially created or can be added
to existing snapshot virtual disks.
Creating A Snapshot Virtual Disk Using The Simple Path
You can choose the simple path to create a snapshot virtual disk if the disk group of the source virtual
disk has the required amount of free space. A snapshot repository virtual disk requires a minimum of 8
MB free capacity. The destination of a snapshot repository virtual disk is determined based on the free
capacity available in the disk group. If 8 MB of free capacity is not available in the disk group of the source
virtual disk, the Create Snapshot Virtual Disks feature defaults to the advanced path. In the advanced path
option, you can choose to place the snapshot repository virtual disk in another disk group or you can use
unconfigured capacity on the storage array to create a new disk group. For more information, see
Creating A Snapshot Virtual Disk Using The Advanced Path .
About The Simple Path
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.
Preparing Host Servers To Create The Snapshot Using The Simple 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.
• You can create concurrent snapshots of a source virtual disk on both the source disk group and on
another disk group.
Before creating a Snapshot Virtual Disk, note that:
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