Dell POWERVAULT MD3600I - Manual (Page 155)

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:
• The following types of virtual disks are not valid source virtual disks:
– Snapshot repository virtual disks
– Snapshot virtual disks
– Target virtual disks that are participating in a virtual disk copy
• You cannot create a snapshot of a virtual disk that contains unreadable sectors.
• You must satisfy the requirements of your host operating system for creating snapshot virtual disks. Failure to
meet the requirements of your host operating system results in an inaccurate snapshot of the source virtual disk
or the target virtual disk in a virtual disk copy.
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