Glossary

database server

A computer with a large database stored on it, such as the SAP R/3 or Microsoft SQL database. A server has a database that can be accessed by clients.

Dbobject (Informix Server specific term)

An Informix Server physical database object. It can be a blobspace, dbspace, or logical log file.

DC directory

The Detail Catalog (DC) directory consists of DC binary files, which store information about file versions. It represents the DCBF part of the IDB, which occupies approximately 80% of the IDB. The default DC directory is called the dcbf directory and is located in the <Data_Protector_home>\db40 directory on a Windows Cell Manager and in the /var/opt/omni/server/db40 directory on a UNIX Cell Manager. You can create more DC directories and locate them as appropriate to you. Up to 10 DC directories are supported per cell. The default maximum size of a DC directory is 4 GB.

DCBF

The Detail Catalog Binary Files (DCBF) part of the IDB stores information about file versions and attributes. It occupies approximately 80% of the IDB. One DC binary file is created for each Data Protector medium used for backup.

delta backup

A delta backup is a backup containing all the changes made to the database from the last backup of any type.

See also backup typesdevice

A physical unit which contains either just a drive or a more complex unit such as a library.

device chain

A device chain consists of several standalone devices configured for sequential use. When a medium in one device gets full, the backup automatically continues on a medium in the next device in the device chain.

device group (EMC Symmetrix specific term)

A logical unit representing several EMC Symmetrix devices. A device cannot belong to more than a single device group. All devices in a device group must be on the same EMC Symmetrix unit. You can use a device group to identify and work with a subset of the available EMC Symmetrix devices.

device streaming

A device is streaming if it can feed enough data to the medium to keep it moving forward continuously. Otherwise, the tape has to be stopped, the device waits for more data, reverses the tape a little and resumes to write to

G-11