Use --redo-only option when preparing a second incremental backup

[jag]

Hello,

in http://www.percona.com/doc/percona-xtrabackup/1.6/innobackupex/incremental_backups_innobackupex.html we see that when executing --apply-log for the incremental backup the --redo option is omitted in the second incremental.

First we have:

innobackupex --apply-log --redo-only BASE-DIR --incremental-dir=INCREMENTAL-DIR-1

Then:

innobackupex --apply-log BASE-DIR --incremental-dir=INCREMENTAL-DIR-2

The lack of ‘–redo-only’ is a typo or it is necessary?.
If it is not a typo what is the difference between the first and subsequents incremental backups which changes the procedure?

Thanks

[mirfan]

–redo-only is not typo. The second backup with INCREMENTAL-DIR-2 assumed it’s the last backup.
–redo-only option skips rollback and it should be excluded from the last backup. --redo-only option is used in full + incremental backup scheme.

Quoted from the manual:
Note: --redo-only should be used when merging all incrementals except the last one. That’s why the previous
line doesn’t contain the --redo-only option. Even if the --redo-only was used on the last step, backup would
still be consistent but in that case server would perform the rollback phase.

[jag]

Thanks a lot for your answer, Mirfan.

The incremental backup was correctly restored. However I have another problem with incremental backup + partial backup, I will open other thread for it