Estimating Catalog Size - HP BB118BV - StorageWorks Data Protector Express Package User's Manual & Technical Reference

NOTE:
The backup device on the other file or application server can be used to help restore the file or application
server that failed.
4.
Suppose the Backup Server fails and the Data Protector Express catalog is lost. While the loss of
the Backup Server is significant, the file or application servers are not impacted and they can
continue to perform their tasks. Backups can still be run from another machine on the network or,
if need be, from the file or application servers themselves. Since the catalog was lost, it will
have to be imported from existing tapes. This step, however, is not crucial and can be run when
convenient, as long as careful backup procedures are followed (that is, no important tapes are
overwritten and a full backup job is run immediately).
The advantages of this arrangement extend to any backup strategy or network arrangement. In general,
consider placing the Data Protector Express catalog on a machine separate from the most important
data. At the very least, consider locating the catalog on a separate volume.
For more information on restoring a corrupted catalog, see

Estimating catalog size

Before deciding where to locate the catalog, consider how large the Data Protector Express catalog
might eventually become.
The size of the catalog is primarily a function of the number of ...
• the number of files backed up,
• the number of versions of each file retained with the selected media rotation, and
• the number of disaster recovery (DR) images stored.
Other objects in the catalog, such as users, jobs, and their properties, contribute to the size of the
catalog. However, because files are by far the most numerous objects in the catalog, these other objects
can be ignored for estimating the catalog size.
The size of the catalog can be estimated with the following calculation ...
File object space = (# of files) * 782 bytes
Version object space = [((# full backups in rotation) * (# of files)) + ((# incremental backups in rotation) *
(# files) * (% files in each incremental))] * 61 bytes
Temporary space = (# of files) * 348 bytes
Disaster recovery image space = (# of DR images from Windows XP/2003 or earlier) * 80MB + (# of
DR images from Windows Vista/2008 or later) * 200MB
Catalog size = File object space + Version object space + Temporary space + Disaster Recovery image
space
Consider the following example. Suppose you have a backup domain consisting of a Windows 20003 file
server which holds 500,000 files and 10 user PCs (5 XP and 5 Vista) with an average of 10,000 local files
each. Your domain is regularly backed up using the GFS-25 automatic rotation schedule. The GFS-25
rotation uses 25 tapes as ...
• 8 daily incremental backups,
• 8 weekly full backups,
• 7 monthly full backups, and
• 2 yearly full backups.
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Tips, Techniques and Strategies
To restore a catalog.