in the backup exec 2012 environment what are the catalogs and the inventories ? I have read the manual but honestly I have not understood. I am sorry for my basic question but it seems that what I have written is not enough for serverfault..
I'm sure you can simply look in the docs...but here's my definition...
Catalog = a list of the files/folders/dates/etc backed up WITHIN a backup file that BUE created. Used to do a restore of files typically. If the catalog has expired in the BUE database, then you'll need to run a catalog on the backup media in order to restore files from them. It tells BUE what is inside the backup media.
Inventory = when run against a Library or Backup-to-Disk-Folder will inventory that location looking for backup files and listing them along with what media set they are in (and therefore when/if they are overwriteable, appendable, etc.).
So, let's say you have an LTO tape from 2 years ago. You'd insert it, then run an Inventory on the tape library/drive. This will tell BUE what is in the drive and what backup media files exist. Then you'd run a catalog against those media files in order to see what actually exists WITHIN those backup media files to be able to restore.
Hope that helps.