I recently had to do a backup of a 30 very large databases within a MySQL instance that had a total of 60+ databases. I did NOT want to back up the other databases. In fact, the other databases had very large tables in them and I had very little disk space, so I could not afford to back them up. In this post I will share what I learned.
I’ve simplified the problem to illustrate the idea. My goal in this post is to backup one database when an instance has many, with mixed InnoDB and MyIsam tables.
- I have 3 databases called dbtest1, dbtest2, and dbtest3, in one instance of MySQL . I only want to back up the tables in database dbtest2
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- Each database has one InnoDB and one MyISAM table
- The InnoDB tables are quite large, and I have limited disk space for the backup
- I am using file-per-table option for all InnoDB tables
The –databases Option
First I tried the–databases=dbname option in the mysqlbackup command line. This option filters all non-innoDB files, including FRM, MYD, MYI etc. .
mysqlbackup –u username –p –databases=”dbtest2” –backup_dir=yourdirectory backup
This translates to:
- Backup all the non-InnoDB files (including frm files) in the database I’ve specified (dbtest2)
- Do NOT backup the non-InnoDB files in any other databases
- Back up all IBD files in the instance
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A full backup of dbtest2 was saved (as outlined above) but the IBD files in all other databases in the instance were also backed up. So this is not the exact option I needed.
The –include Option
Next I added the –include option to filter IBD files in other databases. It’s important to think about the—include option as filtering IBD files (not InnoDB tables, which in my mind include IBD and FRM files)
mysqlbackup –u username –p –databases=”dbtest2” –include=”dbtest2” backup_dir=yourdirectory backup
This translates to:
- Backup all the non-InnoDB files (including frm files) in the database I’ve specified (dbtest2), as before
- Do NOT backup the non-InnoDB files in any other databases, as before
- Back up all IBD files only in the dbtest2 database
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This gave me exactly what I wanted – one directory with all the IBD, FRM, MYD, and MYI files for dbtest2. All other databases are completely ignored, so I did not run out of disk!.
Note that the –include syntax does not permit you to list more than one database at a time. However, it does allow you to use regular expression syntax such as :
–include=db. (include all databases starting with db followed by any character)
- or
–include=dbtest[12] (include dbtest1 and dbtest2)
Compression
Consider trying compression – in my original scenario, I also used compression which was a great help and compressed my 1300 gigabyte files 80% in the backup. Of course the downside to compression is you must decompress to restore, but it is definitely worth considering if you have space limitations.
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