Storix Software SBAdmin User Guide - Manual (Page 18)

Storix System Backup Administrator 18 Version 8.2 User Guide
Tape Devices
A tape backup device may consist of a single tape in a single tape drive, multiple tapes from a single tape
drive, or multiple tapes from multiple tape drives. For simplicity, the term "tape"
or "tape backup" may refer
to any of these.
When writing backups to tape, each filesystem or raw storage device (partition, logical volume, metadisk,
ZFS device, etc) is stored in a separate backup image. This allows tapes to be quickly forwarded to the
desired data for faster restores.
A tape might contain a single backup job, and the job might contain only a single client. The tape may also
contain multiple backup jobs, each containing one or more clients. A single client backup on the tape is
identified by its
backup sequence number . The backup sequence number begins with 1 (the first client
backup on the tape) and is incremented for each additional client backup appended to the same tape.
The Backup Administrator keeps track of the contents of a tape. At any time, the admin may display or print
the backup label , which contains a list of the client backups and corresponding sequence numbers. It is
usually a good idea to print the backup label and store it with the backup tape. If the printed label is lost,
the
Backup Label ID may be read from the tape and the label information may again be displayed or
printed.
A backup tape may also be identified by a Tape Label ID . If desired, the user can write a unique tape label
ID to each tape that will be used with the Backup Administrator . Often tapes come with physical tape labels
with a unique tape ID printed on it. This label may be physically applied to the tape and the tape label ID
may be written to the tape media using the
Backup Administrator . After doing so, that tape label ID will be
associated with any backups written to that tape. The backup label may be displayed given the tape label
ID and the tape label IDs used with a backup will be displayed within the backup label.
The backup retention policy ensures that you do not accidentally write over a prior backup by reading the
label from the tape before each backup is performed to the beginning of the tape. If the backup label is
current, the backup will fail with an error message before the tape is overwritten. Tapes may be overwritten
only after the tape is
expired . By manually expiring a tape, the label information is removed from the
database and the tape may be reused. The admin may also set the backup retention policy (also known as
the overwrite policy) to allow current backup tapes to be overwritten. If so, the tape label will be
automatically expired when a new backup is written at the start of the tape. The global overwrite policy may
be explicitly overridden for each backup job.
Multiple tape drives may be combined into a single device, providing increased performance and capacity.
There are three types of tape devices you can configure for performing sequential, parallel or multi-copy
backups. Tape devices may also be configured as a
Sequential Autoloader or a Random Tape Library .
Refer to Types of Devices as described in detail in the Devices section for a complete description.
Also, when configuring a client (Network Edition), you may specify a tape drive name to be used for local
System Backups of that client (often referred to as SBTAPE). This backup device option will then appear
when you choose to configure a backup job to run locally on the client, requiring no server or network
traffic. See Clients for more details.
Directory Devices
Any backup may be written to a directory on the backup server. In addition, full system backups may be
written to the local client’s
configured System Backup Disk (SBDIR). This includes portable devices such as
USB disks and RAID arrays such as SAN-attached disks. With disk backups, each filesystem or logical
volume within the backup is stored in a different file, so access to the data is much faster than from tape,
where it is usually necessary to rewind and forward a tape to a particular backup and filesystem to restore
select data.
When you configure a directory device for a server (or local system for Workstation Edition), you can name
the device anything you wish. Usually, you can simply use the directory itself for the name. You may also