For every server user, database backup is quite necessary. Database backup is the duplication of all data in the database, so users can use database backup to realize data disaster recovery. Commonly seen database backup types include full backup, transaction log backup, differential backup, and file backup. For detailed information about the 4 types, please look at the following introduction.
Full backup: just as its name implies, database full backup is a duplication of all information in database, including user table, system table, index, view, storage process, and so on. However, full backup is a piece of time-consuming work and needs much storage space, so most enterprises or organizations only use it in fixed time.
Transaction log backup: transaction log is a standalone file which records changes of database. When backing up transaction log, we just need to copy changes to database as of last time. Therefore, transaction log backup just costs little time. In order to enhance robustness of database, we suggest backing up transaction logs per hour or more frequently.
Differential backup: differential backup only backs up a part of information in database. It does not use transaction log but use a new image of database instead. Differential backup just contains changes since the previous time, so it can be saved and recovered quickly. Users are recommended making differential backup per day.
File backup: Database can be constituted by lots of files on hard disk. If a database is so huge and users are unable to complete backup in one night, users can backup a part of files per night by making use of file backup.
Now that there are many ways to backup database, which is most suitable for you? To solve this problem, ask yourself the following 3 questions:
- What does your service-level agreement dictate about recovery time?
- What types of database backup does your backup app support?
- What are the policies regarding storing backup tapes offsite?
Fully considering these questions, you can choose the best database backup type for your data.