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The ProxyHost iDataAgent can be implemented in conjunction with the VSS Enabler to conduct backup operations using a VSS Hardware Provider. ProxyHost uses the snapshot to back up large amounts of data without using production server resources. Because the backup does not occur on the production server, resources on the production server are not affected by this operation.
VSS Hardware providers allow you to create shadows without imposing a load on the local client, or production server. For the purposes of VSS, the snapshot is referred to as a shadow. Furthermore, an option to make the shadow transportable has been provided, which allows you to mount, or import, the shadow on another client. If a shadow is not marked as transportable, you will not be able to mount the shadow.
When using VSS, the system will use the default provider to create the shadow. If you have installed a hardware provider, this becomes the default provider (VSS will use the hardware provider in place of Microsoft Shadow Copy. The Microsoft Software Shadow Copy provider cannot be used for snapshots if you have a VSS hardware provider installed. The VSS hardware provider will have a higher precedence than the Microsoft Software Shadow Copy provider and so QR Volume creation or backups with the Shadow Copy Provider will fail.
If there are multiple hardware providers residing on the same machine, note that not all hardware providers will support the same volumes. For example, the EMC provider will only support disks on the CLARiiON, the HDS provider will only support HDS disks, etc. VSS determines if a supports the volume to be snapped.
The diagram that follows shows a sample ProxyHost configuration in a VSS Hardware Snapshot Provider environment.
Data from the production server is snapped by the VSS Hardware Provider; this snapshot is referred to as a shadow. The shadow is imported to the Backup Host, and ProxyHost begins the backup. When the backup completes, the shadow is deleted.
The ProxyHost iDataAgent is installed on the production server only. The same File System iDataAgent is installed on both the production server and the backup host. In addition, the VSS Enabler is installed on the production server and backup host.
During a ProxyHost backup, the following sequence of events takes place:
The following must be done before creating VSS Hardware shadows.
For more information and procedures, see Deployment - Quick Recovery Agent and Deployment - ProxyHost iDataAgent.
Before using VSS, review the following information:
When restoring data that was backed up from Exchange using the Log truncation
feature in combination with a VSS hardware provider snapshot, and the
*.chk file was located on a different volume, it
must be manually deleted before attempting to mount Exchange Stores after a
restore procedure. This will ensure that you will not have a *.chk
file which does not match the logs and database being restored, and thus be
unable to bring up the Exchange Stores after the restore. Exchange will create a
new *.chk file based on the log you restore.
Example:
The System path location of the storage group is:
C:\Program Files\Exchsrvr\mdbdata, and not on the volume where the
snapshot was taken.
To perform a data protection operation using this Agent a specific Product License must be available in the CommServe® Server.
Review general license requirements included in License Administration. Also, View All Licenses provides step-by-step instructions on how to view the license information.
VSS Hardware snapshot also requires a license for the VSS Enabler.