HP StorageWorks SAN Virtualization Services Platform Administrator Guide (5697-0934, May 2011)

Making sure that VSS works with the VSM virtual disks
The following procedure describes how to test VSS functionality with the VSM virtual disks before
you integrate the VSS with the backup software. The procedure uses the VShadow utility from the
Microsoft Windows Software Development Kit (SDK). You also can use VShadow as a standalone
tool for creating consistent PiTs and snapshots for backup and recovery purpose. To read more
about the VShadow, access:
http://msdn.microsoft.com/en-us/library/bb530725.aspx
1. On the host server, open a DOS command prompt window and use the change directory
command (CD) to navigate to the installation folder for the SVSP VSS hardware provider.
The default folder is C:\Program Files\Hewlett-Packard\SVSP VSS Hardware
Provider\.
2. To show the help menu of the VShadow utility, type vshadow -? and press Enter.
3. On the VSM, create a virtual disk and present the virtual disk to the host server on which you
plan to test the integration of VSS with the VSM virtual disks.
4. From Computer Management on the host server, run a scan for hardware changes.
5. After the scan finishes, open Disk Management.
6. Identify the new disk and create the new disk as a single primary partition with a new drive
letter. In the following steps, the examples of commands assume that the VSM virtual disk was
created and assigned to use drive letter m:.
7. In the DOS command prompt window on the host server, type vshadow.exe -p m: and
press Enter.
This command creates a persistent shadow copy on drive m:. The drive label is the letter that
you gave to the new drive in step 6.
The shadow copy is a read-only point-in-time replica of the original volume contents. A persistent
shadow copy remains in the system until you, or the backup application, initiates an explicit
command to delete the shadow copy. Non-persistent shadow copies are automatically deleted
when the Vshadow creation/import process exits, unless you set either of the Break flags [-b
or -bw] on the shadow set before exit. You can instruct VSS to create a synchronous shadow
copy on several drives by adding the target drive letters to the command. For example,
vshadow.exe -p m n o:
After VSS prepares the volume for snapshot on the host, VSS creates a PiT and a snapshot for
that virtual disk on the VSM. This command creates the snapshot with read/write permissions
to the same server. Although the server sees the snapshot, the snapshot is not mounted
automatically on the server.
To generate a shadow copy in which the snapshot is not presented to any host, type
vshadow.exe -t=<file.xml> m: and press Enter.
You can see the results of running the VShadow utility in the DOS command prompt window.
VSS assigns a shadow copy set number to the snapshot that VSS creates. You can use the
shadow copy set number for correlating the VSS objects on the host server with the
corresponding PiT and snapshots that were created on the VSM. The shadow copy set number
appears in these locations:
• The messages on the command prompt windows
• The names of the PiT and the view that are created on the VSM
Figure 27 (page 72) shows an example of an output messages on the command prompt
window. Note the SNAPSHOT ID number and the shadow copy set number.
Installing and configuring Microsoft VSS with VSM virtual disks 71