hi,
An important factor when designing your backup system is to calculate how
much disk space you need to store your NetBackup catalog. Your catalog keeps
track of all the files that have been backed up. The catalog’s size is directly tied
in to several variables, including the frequency of your backups, the number of
files being backed up, the path length for each file being backed up, and your
retention periods. On average, the size of your catalog can be between 1% to 2%
(or higher) of the total data being tracked.
To calculate your NetBackup catalog size, you need to know how much data you
will be backing up for full and incremental backups, how often these backups
will be performed, and for how long they will be retained. Here are two simple
formulas to calculate these values:
Data being tracked = (Amount of data to back up) * (Number of backups) *
(Retention period)
NetBackup catalog size = 120 * (number of files)
Note: If you select NetBackup’s True Image Restore option, your catalog will be
twice as large as a catalog without this option selected. True Image Restore
collects the information required to restore directories to their contents at the
time of any selected full or incremental backup. Because the additional
information that NetBackup collects for incremental backups is the same as that
of a full backup, incremental backups take much more disk space when you
collect True Image Restore information.
Example: Calculating the size of your NetBackup catalog
Assumptions:
Amount of data to back up = 100 gigabytes
Incremental backups = 20% of all data
Full backups per month = 4
Retention period for full backups = 6 months
Incremental backups per month = 30
Retention period for incremental backups = 1 month
Solution:
Size of full backups = 100 gigabytes * 4 * 6 months = 2.4 terabytes
Size of incremental backups = (20% of 100 gigabytes) * 30 * 1 month = 600
gigabytes
Total data tracked = 2.4 terabytes + 600 gigabytes = 3 terabytes
NetBackup catalog size = 2% of 3 terabytes= 60 gigabytes
Based on the previous assumptions, it will take 60 gigabytes of disk space to hold
the catalog. Compression can reduce the size of your catalog to one-sixth or less
of its uncompressed size. When the catalog is decompressed, this is only done
for the images and time period of the particular system that you need to restore.
regards,
Srikanth.
