Storage Area Network: Architecture

Data Management

SAN backup reduces data management costs by making it economical to provide shared tape backup support to all servers connected to the SAN. This section will explore these benefits of SAN backup. As an example, assume a SAN is composed of a four-server installation in which each server has 100 GB of disk storage.

High Speed Backup

SAN backup provides a high-speed data path to all the servers attached to the SAN. This will reduce the time for backup. Consider the example above. If one PowerVault 130T were shared between all four servers (centralized backup from previous section), it would take approximately 16 hours to back it up: 1 hour for the 100 GB server directly connected to the library and 15 hours to back up 300 GB on the other three servers over the network. With a Fibre Channel-to-SCSI bridge, all the servers would be directly connected to the library and the backup could be done in as few as 4 hours.

Remote Backup

Remote SAN backup can be used to consolidate backup for all servers in a building or a corporate campus to a single and controlled location. It would no longer be necessary to collect tapes from multiple locations for storage. A secure centralized location can receive the backups for all servers within a 10-km radius.

Disaster Recovery

Disaster recovery is only successful when mission critical data has been restored and made available to the user base. It ensures data survivability. One of the most important requirements to successfully recover from a disaster is to ensure that a backup data set survives the disaster. In a worst-case disaster, the original equipment and data would be lost or destroyed. Redundancy techniques like RAID and high availability clustering do not protect you from this type of disaster. Businesses have continued to use offsite media rotation/storage and replication/remote mirroring to ensure disaster recovery. Even a daily backup, if not rotated offsite, cannot protect data from a site disaster.