By Harald Burose

Remote and branch offices provide a challenge for the backup administrator particularly if there are no IT resources in the remote office. Traditionally a small tape library like an MSL would have been placed in the remote office for backup. Tapes would be taken offline from the library for disaster recovery (DR) protection. That process works with IT staff in the remote office but without IT staff it becomes practically unmanageable. With backup to disk, tape handling is no longer required in the remote office.  However, the data for DR protection still needs to be moved offsite. The data could be moved offsite using replication technology but if full backups are always replicated, the bandwidth of the replication link must be substantial which is impractical financially. Also the capacity of the disk device must be configured in a way that it can be self sufficient and allow primarily for local restores. Without any advanced technologies this capacity also becomes a cost concern.

Thanks to De-Duplication, these problems can now be addressed. If the device put into the remote office supports de-duplication, the number of versions that can be kept locally for recovery are greatly increased. Due to the fact that the de-duplication device only stores the net change that is created on the systems, the device capacity can be utilized much better.

De-Duplication also helps when it comes to moving data offsite or to a remote data center. Traditionally all data sets would have to be transferred either physically via tape or electronically via replication. If the backup device supports De-Duplication and only stores the delta, the replication can focus on the delta rather than the full data set. This greatly reduces the bandwidth requirements for the replication link.

How is all of that managed with HP's Data Protector? Data Protector's cell concept allows you to have a cell in the remote office and another cell in the central data center. Both cells can be managed from a single user interface by simply connecting the interface to the different cell manager. In the central data center, the replicated virtual tapes need to be imported into the local cell by reading only the catalog information from the virtual tape. Once that is done, the central cell manager has full knowledge of the content on the tape and can use object copy technology to copy it to physical tape media for long term retention. It is important for the virtual tape technology to support access by Data Protector of the target virtual tape system in the replication setup without any implications on the replication process of other tapes. For the backup in the remote office, Data Protector's full application support can be leveraged so that remote Exchange or SQL servers can be protected. Data Protector's built-in bare metal disaster recovery capabilities also allow the use of a feature called Disk Delivery for DR. This basically creates a DR bootable disk in the central data center that only needs to be shipped to the remote data center and placed in the server that needs to be recovered. This is a great mechanism to get full system recovery done in case the data is no longer in the remote office backup to disk device for local recovery.