Some data loss with backup and restore in SQL Server 2008

Question

We have developed and delivered a database-driven application about 1 and half a year ago. During this time, they have backed up database, re-installed software and restored database for a few times. Also they have sent us their database afew times to perform some update to the db structure. They have used the built-in backup and restore capability of the software. The software is using SMO (SQl Server Management Object) to perform backup/restore operations.

They now claim that some of their data has been lost during recent backup and restores.

Is such a claim possible or is just their data entry fault?

I have checked their db manually and data they have been added was not there.

Was there any report on SMO bug?

Answer 1

Backup and restore are critical facilities in SQL Server. They always, always, always backup the database consistently (point-in-time). You cannot backup or restore in a way that looses a part of the data or introduces other inconsistencies. SQL Server always prevents you from doing that with an error message.

(The myth that data loss might be possible comes from other RDBMSs like MySQL where backups were a challenge a few years ago).

The problem is elsewhere: In the DML executed on the database.