When we backup a database file in SQL the size of the backed up databse increase 20 times that the intila databse
How/what command are you using for backing up? What are the sizes of your data file (.mdf) and your log file (.ldf)?
Did someone accidently turn of backup compression or not include it in a new script for doing the backups?
Log backup perhaps? (and database TLog has not been backed up yet / often)
Does the Full backup include the LOG perhaps (I can't remember, I know it does something at the end to catch anything that has changed "during" the Full backup)
We always do a Log Backup immediately before a Full Backup in the expectation that that might reduce the stuff in the Full backup, and also so that for a restore the first Log Backup taken after the Full Backup does not also contain (lots of?!!) stuff that was for transaction that were committed before the Full Backup (i.e. if the previous Log Backup was some time / a lot of time before the Full backup was started)
Are you appending your backup? Is it now 21 times the size of the initial DB?
The backup file contains multiple copies of the database since it is not being "initialized" or "formatted" with each backup.
Go to the 'Options' tabl on the "Back Up Database" dialog box, and select the "Overwrite all existing backup sets"