Backups for SQL Servers are always necessary to recover data in case of a corruption. SQL Servers have a large amount of data in their database and any damage to this data could lead to big problems. To implement it, a reliable backup and restore strategy needs to be planned out by the administrator so that even if some data is lost, it can be quickly restored without any impact on the organization’s operations. A well thought out backup and restore strategy can help increase the availability of data and decrease data loss.
But while planning these strategies it is also important to take into consideration the available resources and the current environment. As mentioned, there are two parts to the backup and restore strategy:
- Backup: This part involves deciding the frequency and type of backups, the speed and nature of the hardware that would be needed for the process, the testing strategy of the backups, and how and where the backups would be stored.
- Restore: The restore strategy involves deciding which the restoration process should take place to maximize data availability and who should be responsible for restoring the data. It is also important to document all the processes for future reference.
The following factors should be taken into consideration while trying to design a backup and restore for SQL server
- All the backups should be tested. If a backup has errors in it then the user won’t be able to restore it to get back the lost data
- The strategy should focus on the requirement of the organization in terms of availability and loss of data
- All the constraints in resources should be accounted for including storage space, hardware, and security of the saved backups
What is SQL Server BAK File
With a .bak file extension, SQL Server BAK file is a backup file of the SQL Server database. It contains exactly the same data as the main database and this backup file can be restored to retrieve data which might have been corrupted in the main database.
The BAK files can only be opened and accessed through a proper restoration process. They cannot be opened directly. If the user is going forward with the restoration process, it is important to test and check if the backup files are in the right condition. BAK files can either be healthy or they can be corrupted and absolutely unusable.
To test the BAK file, you can use Restore Verify Only command which checks the BAK files to make sure they are complete and the data in them is readable. Through this command, it’s easy to know if the SQL Server will be able to read the backup file in case a restoration would be required. The command can be used for backup files created through both SQL Server Management Studio and Transact-SQL.
How to restore SQL Server BAK file
- First of all, open SQL Server Management
- Login to the SQL Server whose data you want to restore
- Now, right click on the ‘Database’ file on the left and select ‘Restore Database’
- Click on ‘From device’ and a new window will open up
- Click on ‘Add’ and browse the location of the BAK file
- Select BAK file and click OK
- Now a new window open up which will prompt you to select all the backups that need to be restored. You need to check both the full backup and transaction log of the selected backup
- Click OK and the restoration process will begin. Once it’s done, you will get a confirmation message.
Corruption in SQL backup files
SQL Server BAK files can get corrupted due to numerous reasons. It might be because of a virus attack on the system where the files were stored. Many times when the backups are created they are already corrupted. This could be because the tables in the SQL database were already corrupted and never checked for any corruption that is why it is important to always test backup right after creating them.
How to recover corrupted SQL backup files
SQL Backup recovery cannot be done manually and you need to use a third party software for that. It is important to use an extremely efficient and reliable software for BAK recovery because corrupted backup files are very critical and a small mistake could easily destroy the data in them.