Accounting For Catalog Size; Backup Server And Machine Platforms; Strategies For Faster Jobs - HP BB118BV - StorageWorks Data Protector Express Package User Manual

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 Restore Catalog command on page 145.
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 media in the backup set, the number of
files backed up and the number of versions of each file on valid media. To a lesser extent, the number of
objects in a catalog and the properties of those objects affect the size of the catalog.
In its catalog, Data Protector Express assigns
40 bytes for each version of a file,
•
128 bytes for each catalog object, and
•
1024 bytes for the properties associated with objects.
•
You can use these figures to estimate the size of the catalog. Files are by far the most numerous of the
objects in the catalog, so much so that the size of the other objects (such as users and jobs) is negligible.
Each file that is backed up is assigned 128 bytes and is made part of the catalog. While this figure can be
significant, the number of versions for that file in the catalog is more important when predicting the size
of the catalog. This is because there might be as many as 20 or 30 versions of a particular file in the
catalog. (Files only have properties associated with them when they are assigned permissions or storage
streams, but generally, since most files inherit their permissions from other objects, the 1024 bytes
assigned for properties can be ignored.)
Consider the following example. Suppose a file or application server which holds 100,000 files is
regularly backed up using the GFS-25 automatic rotation schedule. Because there are 25 tapes in this
backup set, there are potentially 25 versions of each of these files (although in practice, there will be
fewer versions since most of the jobs are incremental). You can predict the size of the catalog as follows:
[(# of files) * (128 bytes)] + [(# of versions) * (# of files) * (40 bytes)], or
[(100,000) * (128 bytes)] + [(25) * (100,000) * (40 bytes)] = ~108 MB.
Finally, consider both the operating system and the hardware of the machine that will contain the backup
server. For multi-user network installations, we recommend placing the catalog on a high-speed, high-
capacity server. For example, in a Windows environment, place the catalog on a Windows NT (or later)
server that has a fairly current CPU and adequate RAM.
For single machine installations, Data Protector Express runs adequately under Windows, NetWare, and
Linux.

Strategies for Faster Jobs

Data Protector Express is designed to run jobs quickly and efficiently on various network platforms and
arrangements. This section will help you plan your backup strategy and network installation to maximize
Data Protector Express speed and efficiency.