10 DBCC CHECKDB Best Practices

DBCC CHECKDB is a vital tool for keeping your SQL Server databases healthy and free of corruption. But like any tool, it needs to be used correctly in order to be effective. In this article, we’ll discuss 10 best practices for using DBCC CHECKDB. By following these best practices, you can ensure that your DBCC CHECKDB runs are successful and that your databases remain healthy.

1. Run DBCC CHECKDB regularly

DBCC CHECKDB verifies the physical and logical integrity of all the objects in a database. It does this by checking for allocation errors, consistency errors, and torn page errors.

If DBCC CHECKDB finds any errors, it will report them in the output. You can then take appropriate action to fix the errors. For example, if DBCC CHECKDB reports a torn page error, you can restore the database from a backup.

It’s important to run DBCC CHECKDB regularly because it can help you avoid data loss. If you don’t run DBCC CHECKDB regularly, you might not discover errors until it’s too late to do anything about them.

You should also run DBCC CHECKDB before you make any major changes to a database, such as adding a new column or changing the data type of a column. This is because DBCC CHECKDB can detect errors that might be caused by the change.

2. Use the WITH TABLOCK option if you can

If you’re not familiar, DBCC CHECKDB is a database consistency checker that verifies the physical and logical integrity of all the objects in a given database. It’s an important tool for keeping your databases healthy, but it can be a resource-intensive operation.

One way to reduce the impact of DBCC CHECKDB is to use the WITH TABLOCK option. This option tells DBCC CHECKDB to lock the entire table while it’s running the consistency checks. This can help to improve performance by reducing contention for resources.

Of course, there are some caveats to using this option. For example, you should only use it if you’re sure that no other processes will need to access the table while DBCC CHECKDB is running. But if you can use it safely, it can be a helpful performance optimization.

3. Don’t run DBCC CHECKDB on a production server during business hours

DBCC CHECKDB is a resource-intensive operation that can cause performance issues on your production server. If you must run it during business hours, make sure to schedule it during a time when usage is low, such as early in the morning or late at night.

It’s also a good idea to run DBCC CHECKDB on a test server before running it on your production server. This will allow you to identify any potential problems so that you can fix them before they impact your live environment.

4. If possible, use Ola Hallengren’s SQL Server Maintenance Solution to schedule and execute your DBCC CHECKDB jobs

Ola Hallengren’s SQL Server Maintenance Solution is a free, open-source tool that automates many of the tasks associated with maintaining a SQL Server database, including running DBCC CHECKDB. It offers a number of advantages over using SQL Server Agent jobs to run DBCC CHECKDB, including the ability to:

– Schedule different frequency levels for different databases
– Automatically email the results of DBCC CHECKDB runs
– Perform additional maintenance tasks, such as index and statistics maintenance, in the same job

If you are not able to use Ola Hallengren’s SQL Server Maintenance Solution, you should still use SQL Server Agent jobs to schedule your DBCC CHECKDB runs.

5. Check for corruption before upgrading or migrating databases

If you don’t check for corruption before upgrading or migrating databases, you might end up moving corrupt data to a new environment. This can cause all sorts of problems, including data loss and downtime.

To avoid this, always run DBCC CHECKDB on your source database before upgrading or migrating it. This will help ensure that you’re only moving clean data to your new environment.

6. Always have a backup plan in case of data loss

If DBCC CHECKDB finds any errors in your database, it’s possible that some of your data may be lost. In order to prevent this from happening, you should always have a backup plan in place. That way, if any data is lost, you can restore it from the backup.

There are two main ways to backup your data: full backups and differential backups. Full backups contain all of the data in your database, while differential backups only contain the data that has changed since the last full backup.

Ideally, you should have both types of backups in place. That way, if DBCC CHECKDB finds any errors in your database, you can restore the data from the most recent full backup. If there is only a small amount of data loss, you can restore the data from the most recent differential backup.

7. Make sure that all database backups are valid

If a database backup is invalid, it means that the data in the backup is not consistent with the data in the database. This can happen for a number of reasons, such as hardware failures, software bugs, or user errors.

If you try to restore an invalid backup, you may end up with a corrupt database. Even if the database is not corrupt, you may not be able to recover all of the data from the backup. For these reasons, it is essential to make sure that all database backups are valid before you attempt to restore them.

The best way to ensure that your database backups are valid is to run DBCC CHECKDB on them regularly. This will check the consistency of the data in the backup and report any errors. If you find any errors, you can then take steps to fix them before you attempt to restore the backup.

8. Have a good disaster recovery plan in place

If your database becomes corrupt, you will need to restore it from a backup. But if you don’t have a recent backup, or if the backup is also corrupt, you will be in big trouble.

That’s why it’s important to have a disaster recovery plan that includes regular backups and testing of those backups. That way, if you do have to restore from a backup, you can be confident that it will work.

9. Test your disaster recovery plan at least once per year

If you’re not regularly testing your disaster recovery plan, you have no way of knowing if it will actually work when you need it. By testing it at least once per year, you can identify and fix any issues before they become critical.

Additionally, regular testing will help you to keep your disaster recovery plan up-to-date. As your database changes over time, so too will your disaster recovery requirements. By testing annually, you can ensure that your disaster recovery plan is always current.

10. Know how to restore from backups

If you run DBCC CHECKDB and it finds errors, you need to be able to restore your database from a backup. That way, you can fix the errors and get your database up and running again as quickly as possible.

There are two ways to restore from backups:
1) using SQL Server Management Studio (SSMS), or
2) using T-SQL commands.

Both methods have their own advantages and disadvantages, so it’s important to know both.

Using SSMS is the easier method, but it requires you to have a full backup of your database. If you don’t have a full backup, you won’t be able to use this method.

Using T-SQL commands is a bit more complicated, but it doesn’t require a full backup. You can use this method even if you only have a partial backup.

No matter which method you choose, make sure you test your restores before you actually need to use them. That way, you’ll know for sure that they work and you won’t have to waste time troubleshooting when you’re already under pressure.