Frequently Asked Questions¶

Do I need an InnoDB Hot Backup license to use Percona XtraBackup?¶

No. Although innobackupex is derived from the same GPL and open-source wrapper script that InnoDB Hot Backup uses, it does not execute ibbackup, and the xtrabackup binary does not execute or link to ibbackup. You can use Percona XtraBackup without any license; it is completely separate from InnoDB Hot Backup.

What’s the difference between innobackupex and¶

innobackup?¶

Because innobackupex is a patched version of Oracle ’s innobackup script (now renamed to mysqlbackup), it is quite similar in some ways, and familiarity with innobackup might be helpful.

Aside from the options for specific features of innobackupex, the main differences are:

• printing to STDERR instead of STDOUT (which enables the --stream option),
• the configuration file - my.cnf - is detected automatically (or set with innobackupex --defaults-file) instead of the mandotory first argument,
• and defaults to xtrabackup as binary to use in the --ibbackup.

See The innobackupex Option Reference for more details.

Are you aware of any web-based backup management tools (commercial or not)¶

built around Percona XtraBackup?¶

Zmanda Recovery Manager is a commercial tool that uses Percona XtraBackup for Non-Blocking Backups:

“ZRM provides support for non-blocking backups of MySQL using |Percona XtraBackup|. ZRM with |Percona XtraBackup| provides resource utilization management by providing throttling based on the number of IO operations per second. |Percona XtraBackup| based backups also allow for table level recovery even though the backup was done at the database level (needs the recovery database server to be |Percona Server| with XtraDB).”

xtrabackup binary fails with a floating point exception¶

In most of the cases this is due to not having install the required libraries (and version) by xtrabackup. Installing the GCC suite with the supporting libraries and recompiling xtrabackup will solve the issue. See Compiling and Installing from Source Code for instructions on the procedure.

How xtrabackup handles the ibdata/ib_log files on restore if they aren’t in¶

mysql datadir?¶

In case the ibdata and ib_log files are located in different directories outside of the datadir, you will have to put them in their proper place after the logs have been applied.

Backup fails with Error 24: ‘Too many open files’¶

This usually happens when database being backed up contains large amount of files and Percona XtraBackup can’t open all of them to create a successful backup. In order to avoid this error the operating system should be configured appropriately so that Percona XtraBackup can open all its files. On Linux, this can be done with the ulimit command for specific backup session or by editing the /etc/security/limits.conf to change it globally (NOTE: the maximum possible value that can be set up is 1048576 which is a hard-coded constant in the Linux kernel).

How to deal with skipping of redo logs for DDL operations?¶

To prevent creating corrupted backups when running DDL operations, Percona XtraBackup aborts if it detects that redo logging is disabled. In this case, the following error is printed:

[FATAL] InnoDB: An optimized (without redo logging) DDL operation has been performed. All modified pages may not have been flushed to the disk yet.
Percona XtraBackup will not be able to take a consistent backup. Retry the backup operation.

To avoid this error, Percona XtraBackup can use metadata locks on tables while they are copied:

• To block all DDL operations, use the --lock-ddl option that issues LOCK TABLES FOR BACKUP.
• If LOCK TABLES FOR BACKUP is not supported, you can block DDL for each table before XtraBackup starts to copy it and until the backup is completed using the --lock-ddl-per-table option.