Depending upon various factors, you might find that your catalogs folder grows very large. It's not unusual for it to grow to several gigabytes.
Before reading on, you may wish to read What are catalogs?
The factors that affect the catalog folder size are:
- How much, and what sort of data and resources you are backing up
- How long you are retaining catalogs for
The first factor is probably something that you don't want to change just to reduce your catalog size. How long you wish to retain the catalogs for is something you can change, depending upon your requirements.
To reduce the size of your catalogs, you can reduce the truncate period and the removal period. These are found under Tools, Options, Catalogs. Bear in mind that as you decrease these, you increase the likelihood of having to catalog a tape before you can restore from it.
An alternative is to move the catalog folder to another drive with more available space. There is a Technote on how to do that at http://seer.entsupport.symantec.com/docs/264680.htm