Xtrabackup and MyISAM

MySQL & MariaDB Percona XtraBackup
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Hello,

I use percona-xtrabackup 2.4.24-1.buster on MySQL 5.7 with MyISAM storage engine.

I want to know if incremental backup is working with this storage engine ?

I make some test, but on large DB it doesn’t seam to work. xtrabackup seams to backup all database even if I specify --incremental-basedir parameter.

Regards

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Hi @xfantin .

Incremental backups are currently only supported for InnoDB. MyISAM is basically a new copy every time.

Regards,
Marcelo Altmann

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Hi @Marcelo_Altmann ,

Thanks for you reply. OK for incremental.
I have another question : Can you confirm that xtrabackup can proceed hot backup without locking table with MyISAM storage engine ?

Regards
Xavier

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Hi @xfantin .

No, MyISAM Storage Engine lack capabilities to allow for a hot backup. Xtrabackup take backup of MyISAM tables under FLUSH TABLES WITH READ LOCK (FTWRL).
You can however minimize the time your instance stay under lock by executing xtrabackup with --rsync flag. This way all MyISAM tables will be copies without locking the instance as a first step. A second step then execute the copy of only changed tables under FTWRL minimizing.

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Hi @xfantin,
Would you mind commenting on why you are still using MyISAM? It is, for all intents and purposes, a dead engine with no advanced features like transaction support, ACID compliance, crash recovery, etc.