Dell PowerVault MD3000 Information Update page 8

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 (see "About the Advanced Path" in the User's Guide).
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.
NOTE:
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 the following:
• 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.
NOTE:
Virtual Disk Copy is an Advanced (Premium) feature.
• 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 point-in-time
image of the source virtual disk or the target virtual disk in a virtual disk copy.
NOTICE:
Before you create a new point-in-time image of a source virtual disk, stop any data access (I/O) activity
or suspend data transfer to the source virtual disk to ensure that you capture an accurate point-in-time image of
the source virtual disk. Close all applications, including Windows Internet Explorer
has stopped.
NOTE:
Removing the drive letter of the associated virtual disk(s) in Windows or unmounting the virtual drive in
Linux will help to guarantee a stable copy of the drive for the Snapshot.
Before creating a snapshot virtual disk, the server has to be in the proper state. Perform the following
steps to prepare your server:
1 Stop all I/O activity to the source.
2 Using your Windows system, flush the cache to the source. At the host prompt, type
SMrepassist -f <filename-identifier>
and press <Enter>. See "SMrepassist Utility" in the User's Guide for more information.
3 Remove the drive letter(s) of the source in Windows or unmount the virtual drive(s) in Linux to help
guarantee a stable copy of the drive for the Snapshot. If this is not done, the snapshot operation will
report that it has completed successfully, but the snapshot data will not be updated properly.
NOTE:
Verify that the virtual disk has a status of Optimal or Disabled by clicking the Summary tab and then
clicking the Disk Groups & Virtual Disks link.
4 Follow any additional instructions for your operating system. Failure to follow these additional
instructions can create unusable snapshot virtual disks.
NOTE:
If your operating system requires additional instructions, you can find those instructions in your operating
system documentation.
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Information Update
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, to make sure all I/O activity