In a SAN environment, disk areas used as volumes in other domains (cluster systems and single servers) can be recognized as volumes (shadow volumes) and accessed.
This feature allows a server that does not belong to the domain running the service to recognize and access volumes used in the service via the SAN. Not only the volumes used in the service but also the proxy volumes can also be recognized as shadow volumes by an external server. This capability enables another service, such as backup, restore, batch processing, and data analyses, to run concurrently with the service without imposing loads on the CPU, I/O, and the network of the domain running the service.
One server can recognize and access volumes in multiple domains connected to a SAN as shadow volumes. For example, you can configure a backup server that consolidates the backup and restoration of volumes in multiple domains.
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For the operation mode and the procedure for backup and restore by shadow volumes through an external server, see "6.8 Backing Up and Restoring through an External Server."
Figure 1.43 Backup Server
