Compressed Backup¶
Percona XtraBackup supports compressed backups. A local or streaming backup can be compressed or decompressed with xbstream.
Creating Compressed Backups¶
In order to make a compressed backup you’ll need to use the --compress
option:
$ xtrabackup --backup --compress --target-dir=/data/compressed/
The --compress uses the qpress tool that you can install via
the percona-release package configuration tool as follows:
$ sudo percona-release enable tools
$ sudo apt update
$ sudo apt install qpress
Note
Enable the repository: percona-release enable-only tools release.
If Percona XtraBackup is intended to be used in combination with
the upstream MySQL Server, you only need to enable the tools
repository: percona-release enable-only tools.
If you want to speed up the compression you can use the parallel
compression,
which can be enabled with --compress-threads option.
Following example will use four threads for compression:
$ xtrabackup --backup --compress --compress-threads=4 \
--target-dir=/data/compressed/
Output should look like this
...
170223 13:00:38 [01] Compressing ./test/sbtest1.frm to /tmp/compressed/test/sbtest1.frm.qp
170223 13:00:38 [01] ...done
170223 13:00:38 [01] Compressing ./test/sbtest2.frm to /tmp/compressed/test/sbtest2.frm.qp
170223 13:00:38 [01] ...done
...
170223 13:00:39 [00] Compressing xtrabackup_info
170223 13:00:39 [00] ...done
xtrabackup: Transaction log of lsn (9291934) to (9291934) was copied.
170223 13:00:39 completed OK!
Preparing the backup¶
Before you can prepare the backup you’ll need to uncompress all the files.
Percona XtraBackup has implemented --decompress option
that can be used to decompress the backup.
$ xtrabackup --decompress --target-dir=/data/compressed/
Note
--parallel can be used with --decompress option to decompress multiple files simultaneously.
Percona XtraBackup does not automatically remove the compressed files. In
order to clean up the backup directory you should use
--remove-original option. Even if they’re not removed
these files will not be copied/moved over to the datadir if
--copy-back or --move-back are used.
When the files are uncompressed you can prepare the backup with the
--prepare option:
$ xtrabackup --prepare --target-dir=/data/compressed/
You should check for a confirmation message:
InnoDB: Starting shutdown...
InnoDB: Shutdown completed; log sequence number 9293846
170223 13:39:31 completed OK!
Now the files in /data/compressed/ are ready to be used by the server.
Restoring the backup¶
xtrabackup has a --copy-back option, which performs the
restoration of a backup to the server’s datadir:
$ xtrabackup --copy-back --target-dir=/data/backups/
It will copy all the data-related files back to the server’s datadir,
determined by the server’s my.cnf configuration file. You should check
the last line of the output for a success message:
170223 13:49:13 completed OK!
You should check the file permissions after copying the data back. You may need to adjust them with something like:
$ chown -R mysql:mysql /var/lib/mysql
Now that the datadir contains the restored data. You are ready to start the server.