One day my one friend suddenly found that backup files are larger than database.
As per general standard, there is no way that a particular full database backup file can be larger than the database size. A full backup contains the entire database’s data files that are used, and the active portion of the transaction log during the backup. It is thus possible that the backup file is significantly smaller than the database size, but definitely 100% sure it cannot be larger.
The reason for the large backup file is because the file contains multiple backup sets. A backup file will contain multiple backup sets if it repeatedly back up to the same file, without using the INIT or FORMAT options.
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