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What are the disadvantages of a large differential backup?
A large differential backup loses the advantages of a faster and smaller backup. As the differential backups increase in size, restoring a differential backup can significantly increase the time that is required to restore a database.
How can I reduce the size of my SQL Backup?
In the SQL management studio, right-click your DB, TASKS – BACKUP, then in the window for the backup you’ll see it defaults to the ‘General’ page. Change this to ‘Options’ and you’ll get a different set of choices. The default option at the top is ‘Append to the existing media set’. This is what makes your backup increase in size indefinitely.
How big is the backup file for largedb?
In the end, I drop the #FreeSpace table just to leave things clean. The end result looks like this: As you can immediately see, the “LargeDB” database’s backup file is 96MB but the size of the data file is 90GB and the log file is 10GB.
When does backing up a database shrink the transaction log size?
If that drawer is no longer actively in use (because SQL Server has moved on to the next drawer), then you’re marking that drawer as available to reuse (think of it as throwing all the contents out) Backups don’t change the size of your cabinet (log file).
When do you need a differential database backup?
Differential database backups are especially useful if a subset of a database is modified more frequently than the rest of the database. In these cases, differential database backups enable you back up frequently without the overhead of full database backups.
Where is metadata stored in a differential backup?
Therefore, metadata that is required by a differential backup, such as the log sequence number at which the differential backup begins (the differential base LSN) is stored in the master database.
Why does SQL Server lose differential base information?
When a read-only database is rebuilt, restored, or detached and attached, the differential-base information is lost. This occurs because the master database is not synchronized with the user database. The SQL Server Database Engine cannot detect or prevent this problem.