Storage Efficiency - Technologies

Technologies

Different technologies exist at different and sometimes multiple levels:

Snapshot technology—known formally as "delta snapshot technology"—gives the ability to use the same dataset multiple times for multiple reasons, while storing only the changes between each dataset. Some storage vendors integrate their snapshot capabilities at the operating system and/or application level, enabling access to the data the snapshot's are holding at the system and/or application management layers. Terminology around snapshots and "clones" is currently confusing, and care must be taken when evaluating vendor claims. In particular, some vendors call full point-in-time copies "snapshots" or "clones", while others use the same terms to refer to shared-block "delta" snapshots or clones. And some implementations can only do read-only snapshots, while others are able to provide writable ones as well.

Data deduplication technology can be used to very efficiently track and remove duplicate blocks of data inside a storage unit. There are a multitude of implementations, each with their separate advantages and disadvantages. Deduplication is most efficient at the shared storage layer, however, implementations in software and even databases exist. The most suitable candidates for deduplication are backup and platform virtualization, because both applications typically produce or use a lot of almost identical copies. However, some vendors are now offering in-place deduplication, which deduplicates primary storage.

Thin provisioning technology. This is a technique to prevent under-utilization by sharing the allocated, but not yet utilized capacity. A good example is Gmail, where every Gmail account has a large amount of allocated capacity. Because most Gmail users only use a fraction of the allocated capacity, this "free space" is "shared" among all Gmail users.