Taking regular database backups is essential to provide assistance to businesses recovering from an unplanned event. They enable data restoration from when it was previously saved. Moreover, keeping a copy of the information separately is also vital for protection against corruption or data loss.
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In this guide, we will discuss SQL Server backup types, recovery models, as well as best practices that you should take into account when putting together your backup strategy.
Various Types of Backups in SQL Server
There are different backup types in SQL Server that users have to consider when constructing their backup strategy. Here, we will briefly explain each of these variants and how they work. Microsoft SQL Server supports the following backup forms:
Full Backup: This implies a complete backup of the SQL Server database. It covers every object in the database. It is the most popular and recommended backup type as it enables users to restore their database to the exact same version it was when the backup was taken.
Differential Backup: It backs up only the data that has undergone changes since you created the last full backup. This is why it takes lesser time than a full backup. However, creating several differential backups over time may eventually lead to greater storage requirements.
The size increases because of the addition of changed data in each subsequent backup, and it can grow to become as large as the full backup. Thus, it is important to schedule new full backups (even if they’re less frequent) to avoid extended backup times and oversized differential backups. Otherwise, these excessively-large backups will cause a negative impact on database performance, requiring optimization.
Transaction Log Backup: It is a form of incremental backup. It backs up the transaction log containing the modifications made since the last t-log backup. Log backups can take place quite frequently – even once every few minutes. This enables users to carry out point-in-time restores to reduce data loss.
File/filegroup Backup: This type of backup involves making separate copies of individual data files or files from a filegroup. Users can backup and restore each database file separately as well.
Copy-only Backup: This is a type of SQL Server backup that doesn’t depend on the sequence of traditional backups. When you create a backup, it generally makes changes to the database. These impact the manner in which these backups will be restored in the future. On the other hand, it may sometimes be more useful to create backups that don’t affect the comprehensive backup and restore methods for the entire database.
Creating Backups for SQL Server Databases: What Experts Suggest
Seasoned database professionals recommend a few things when it comes to creating backups of the database. For starters, they suggest using the full recovery method on a daily basis. However, you may create these on alternate days and differential backups every day if the database size exceeds three GB.
Many also advise making daily t-log backups once you’ve created a full or differential backup. You may even schedule one for every four hours, and avoid truncating one manually. If disaster strikes, it’s better to create a backup of the t-log that’s active at the moment. In case there isn’t any t-log backup available, you’ll be unable to restore database activities past the latest available t-log backup. This is likely to hinder point-in-time recovery as well.