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5 Comments Written by Robert on April 24, 2008 – 12:34 pm

As the challenges of backup continue to grow, everyone is looking for new ways to meet these challenges. One of the new backup methods is sometimes referred to as serverless or server-free backup. The more correct name is offhost backup. This backup method uses a separate backup agent located on either a media server or a third-party copy (3PC) device to actually move the data from the client disk to storage.

The backup agent in this case could be either a media server or a third-party copy (3PC) device that implements SCSI Extended Copy commands. Many types of 3PC devices can act as backup agents, such as

Bridge

Router

Robotic library

Disk array

One of the key elements for offhost backups is that the backup must be done from a frozen image. Sometimes this feature is confused with the LAN-free backup feature such as the NetBackup SSO feature. If the requirement is to keep the backup data off the LAN or to do a frozen image backup so that the application can continue to be available, either SSO or frozen image backups will fulfill the need. If the problem is that the backup overhead is too much for the application server to handle, offhost backup is the solution. By using offhost backup, you are moving the disk reads and the tape writes to a separate backup agent who will actually perform this work.

Many people are finding that a single backup domain is no longer an option. This can be due to physical reasons (domains in different geographic locations), business reasons (different domains for business units), or size (too big for a single domain). Finding yourself with multiple backup domains can make the administration much more complicated. In situations like this it is nice to find a feature such as Global Data Manager (GDM) from VERITAS Software. This feature is a fourth tier in the NetBackup architecture. It is a master of masters that provides a single console that allows you to see and manage all of your backup domains. This type of feature makes it much easier to administer distributed backup domains by using a dashboard that gives you, at a glance, the real-time status and health of all your domains.

While backup is a very important part of any enterprise data protection strategy, it alone does not provide for true disaster recovery. Any enterprise DR strategy should include an off-site backup management system such as VERITAS Software’s NetBackup Vault or Gray House Solutions’ Duplication Suite. A vault product is one that enables you to make multiple copies of your backup images, gives you the tools to eject the desired tapes from the robotic library, and provides the reports to track the movement of the tapes while outside the library. The tapes that are outside the library are generally stored at an off-site location. The vault product provides tracking of the tapes in the off-site location, and it notifies you when the images on the off-site tapes have expired and the tapes should be returned to the library for reuse. This is done so if there is a disaster at the primary site, the data will still be available from the off-site tapes.

The requirements for an off-site backup management system are as follows:

A schedule for sending media off-site

A method to determine what data to send off-site

A mechanism to automate the creation of duplicate media (images)

A mechanism to duplicate the catalog

A way to determine which media to retrieve from off-site storage for reuse

A system for tracking both the data and the media while stored at the off-site location

A method for reporting on media shipments

Efficient use of resources

Since this is the cornerstone in any enterprise DR strategy, the selection of the product to fulfill these requirements is very important. Make sure you select a product that gives you all the functionality you need, along with flexibility and ease of use. Vault is generally considered a three-step process:

Duplication of backups.

Backup of the catalog.

Ejecting of media and reporting.

Depending on your individual requirements, you can perform any or all of these steps. With some of the vault products like NetBackup Vault, you can configure the backup session to write to multiple tapes, creating multiple copies of the backups without having to duplicate them. This would fulfill the requirements for the first step. At the end of the backup session, and the duplication session if required, Vault needs to make a tape copy of the catalog to accompany the media as it goes off-site. When it is time to transport the media to an off-site location, Vault should eject the appropriate media and generate the necessary reports to track the media. A part of the reporting is the recall of expired media to be reused.

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