User's Manual

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Glossary

Assigned Disks

Same as Managed Disks. Physical disks that are identified by Storage Center and to which data can be

written. Assigned disks use metadata to track information about volumes on the disk and other assigned

disks managed by the controller.

Asynchronous Replication

After data has been written to the primary storage site, new writes to that site can be accepted without

having to wait for the secondary (remote) storage site to also finish its writes. Asynchronous Replication

does not have the latency impact that synchronous replication does, but if the primary site failed before the

data was written to the secondary site the data that had not yet been written could be lost. See also

replication.

Back End

The component in the Storage Center SAN flow of data writes (server to switch to controller to disks) that

receive data writes. In general, disk drives in enclosures are the back end of the controller. However, a

remote system that is receiving replication data from a local Storage Center is the back end local Storage

Center. See Target System.

Backup

A two step process. A Replay is first copied to a non-volatile disk remote system. In the event of problems

(such as disk drive failures, power outages, or virus infection) resulting in data loss or damage to the original

data, the Replay is retrieved and restored to a View Volume.

Bandwidth

The amount of data that can be sent to or from Storage Center per internal time.

Block Data

Raw data which does not have a file structure imposed on it. Database applications such as a SQL Server

or an Exchange Server transfer data in blocks. Block transfer is the most efficient way to write to disk.