Can you outline the various types of disk backup options available today and explain how they differ from each other?
A virtual tape library is a backup solution in which disk-based storage (typically a SATA or SAS array) is virtualized and presented as tape storage. Virtual tape libraries offer three main advantages. First, they work with almost any existing backup software since the storage media is presented as tape. Second, virtual tape libraries offer better performance than tape because data is being written to disk. Third, virtual tape libraries eliminate the problems commonly associated with streaming data to tape. Although it is common to make a second copy of a virtual tape library's contents on tape, doing so is typically more efficient than backing the original data sources up to tape directly because the data is being read from a centralized storage location.
Deduplication arrays are storage arrays that are specifically designed for backup and recovery purposes. These devices use deduplication to maximize the amount of data that can be stored, and typically also include load-balancing features designed to maximize data throughput. Deduplication arrays may also support hardware-level replication as a way of protecting against failure. However, these devices typically don't emulate tape drives like a VTL. This is less of an issue today, as newer backup software platforms can write data directly to disk.
Integrated backup appliances are systems that offer a deduplicated storage pool with backup software and a media server in one device. These appliances are designed to be entirely self-contained, which allows them to be plugged into the network and rapidly deployed. Because they are self-contained and run hardware and software provided by a single vendor, troubleshooting problems tends to be comparatively easy. Critics of integrated appliances say these systems are not as scalable as other systems and vendor lock-in can also be an issue.
This was first published in October 2013