BACKGROUND IMAGE: iSTOCK/GETTY IMAGES
Serverless backup is a type of network-based backup that seeks to limit the role of production servers in backup procedures. The goal of serverless backup is to facilitate disk-to-tape or disk-to-disk backup without depleting server resources.
Ordinarily, the amount of time a production server can devote to processing requests from applications is limited by the amount of time it must reserve to back up data. Offloading backup procedures from production servers frees the servers up to process more data.
While all serverless backup systems enable disk-to-tape or disk-to-disk backup, vendors who provide this service may map the copy function slightly differently. For example, backup may be performed by an appliance, which can be an actual physical device or a software function in a larger storage management product.
A number of companies offer serverless backup products, including Arcserve with its Arcserve Unified Data Protection (UDP), Dell EMC and its NetWorker software and Veritas Technologies' NetBackup appliances. The CA and Veritas products are based on a process known as disk imaging. These applications use an intelligent agent to make a snapshot copy of pointers to the data. The snapshot copy consists of an image of the pointers, which indicate the location of the data, but is not yet a backup of the data itself. The actual backup still needs to happen, based on the snapshot. The intelligent agent and backup procedures communicate through the Network Data Management Protocol (NDMP).
The Dell EMC serverless backup function has become part of the NetWorker software, based on technology EMC received from its acquisition of Legato Systems in 2003. Proprietary software within the hardware platform is used to mark logical backup objects and to back up data on the list.
Another method of performing a serverless backup is via XCOPY, the extended copy function within SCSI. In this case, the server initiates and manages the backup, but is not involved in actually backing up the data. The SCSI XCOPY command simply tells the data to replicate from one device or location to another.