Hitachi 9900 manual Ctq, Das

Hitachi Data Systems

CTQ

Command-Tag Queuing.

DA

The Data Adapter resides on the CHT and connects the cache boards to the front end.

DAS

Direct Attached Storage.

Data Availability

Data availability refers to the degree to which a computer system is capable of providing data to its users. See also Availability.

Data Copy

A term that refers to remote copy, data duplication, and data migration.

DD

Disk Director.

Data Duplication

Software that duplicates data as in remote copy or point-in-time (PiT) snapshots. Data duplication is differentiated from data migration in that with data duplication, at the end of the process there are two copies of data and with data migration there is only one.

Data Migration Software

Software that migrates data from one storage device to another. This feature is different from data duplication in that at the end of the process there is only one copy of data.

Disaster Recovery

Disaster Recovery is the profession that plans to avoid disasters and to restore services after a disaster. It also indicates the level of preparedness to respond to an interruption in services by implementing a disaster recovery plan to restore an organization's critical business functions.

Downtime

A planned or unplanned interruption in system availability. Planned downtime is usually for scheduled system maintenance and unplanned downtime usually includes business interruptions or disasters. See also Business Interruptions, Disaster Recovery, Business Continuity Planning (BCP), and Availability.

DR

Disaster Recovery.

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