innodb_doublewrite not copied back to proper location

[Rocco]

innobackupex: back to original data directory '/data/mysql'
innobackupex: Copying '/backup/2013-05-28/innodb_doublewrite' to '/data/mysql/innodb_doublewrite'

/etc/mysql/my.cnf:

innodb_doublewrite_file = /log/mysql-bin/innodb_doublewrite

Ubuntu deb installed.
ii percona-xtrabackup 2.1.3-608.precise

Not sure if it's a problem or not (That the doublewrite file will be missing). InnoDB log files are copied to correct destination.
innobackupex: back to original InnoDB log directory '/log/mysql-bin'

[Raghavendra D Prabhu (raghavendra-prabhu)]

It copies the files based on backup-my.cnf I believe, what is the path set in that for innodb_doublewrite_file?

Probably copy-back/move-back should use my.cnf of system than the
backup-my.cnf.

[Raghavendra D Prabhu (raghavendra-prabhu)]

Adding PXC since this can affect it as well (though currently there is another bug preventing this).

[Rocco (rocco)]

cat backup-my.cnf
innodb_doublewrite_file=innodb_doublewrite

cat my.cnf
innodb_doublewrite_file = /log/mysql-bin/innodb_doublewrite

[Raghavendra D Prabhu (raghavendra-prabhu)]

@Rocoo,

What is the my.cnf on source host - just to check if
backup-my.cnf is generated correctly. To see if it is bug in
that.

[Rocco (rocco)]

Well the path I wrote from my.cnf is on the source, and the destination
also for that matter.

On Wednesday, May 29, 2013, Raghavendra D Prabhu wrote:

> @Rocoo,
>
> What is the my.cnf on source host - just to check if
> backup-my.cnf is generated correctly. To see if it is bug in
> that.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1184888
>
> Title:
> innodb_doublewrite not copied back to proper location
>
> Status in Percona XtraBackup:
> New
> Status in Percona XtraDB Cluster - HA scalable solution for MySQL:
> New
>
> Bug description:
> innobackupex: back to original data directory '/data/mysql'
> innobackupex: Copying '/backup/2013-05-28/innodb_doublewrite' to
> '/data/mysql/innodb_doublewrite'
>
>
> /etc/mysql/my.cnf:
>
> innodb_doublewrite_file = /log/mysql-bin/innodb_doublewrite
>
> Ubuntu deb installed.
> ii percona-xtrabackup
> 2.1.3-608.precise
>
> Not sure if it's a problem or not (That the doublewrite file will be
> missing). InnoDB log files are copied to correct destination.
> innobackupex: back to original InnoDB log directory '/log/mysql-bin'
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/percona-xtrabackup/+bug/1184888/+subscriptions
>

[Raghavendra D Prabhu (raghavendra-prabhu)]

Assuming you have xtrabackup 2.1.3 installed on destination host as well, this is an issue caused by incomplete fix of lp:1068470

        $excluded_files = $excluded_files . '|' . $doublewrite_file;

This doesn't handle full paths of doublewrite_file I think.

[Raghavendra D Prabhu (raghavendra-prabhu)]

@Rocco, As per the original fix, the doublewrite buffer it copies is not required after prepare. You can delete that file after prepare/apply-log but before copy/move.

[Alexey Kopytov (akopytov)]

Correct, it's an incomplete fix for bug #1068470.

[Sergei Glushchenko (sergei.glushchenko)]

For those who on XtraBcakup 2.1 please consider upgrading to 2.2.
2.2 has no such issue because it doesn't backup doublewrite file.
Doublewrite file is not really needed for xtrabackup because xtrabackup ensure that backup does not contain partially written pages by design. All pages are verified for consistency by checking their checksums.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PXB-638