The amount of space taken up by a server or other device in a server cabinet. Usually measured in U, example a server being 2U high. 

A method of splitting up data across a set of hard disks, allowing for faster access, more resiliency or a combination of both.

The duplication of information or a hardware component to ensure that should the primary resource fail, a secondary resource can take over its function.

A feature enabling a “remote” user or piece of equipment to gain access to/the use of resources that are not directly connected to it by a physical means. Examples include the ability to “Dial in” to a server to control it from a distance, or viewing your e-mail from a shared computer via the Internet.

Remote mirroring is the process of creating an additional copy of written/stored data at a remote location, enabling a more robust disaster recovery environment. This capability is key for a disaster recovery solution that provides for resilience and access to business critical data.

Replication is the process of duplicating mission critical data from one highly available site to another.

A retrieval of data previously backed up to storage media. A restore is performed if data has been lost or corrupted since the backup.