Compressed backup¶
Percona XtraBackup supports compressed backups. A local or streaming backup can be compressed or decompressed with xbstream.
Create compressed backups¶
To make a compressed backup, use the --compress option along
with the --backup and --target-dir options.
The --compress option uses the qpress tool that you can install with
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.
Percona XtraBackup supports the following compression algorithms:
quicklz
To compress files using the quicklz compression algorithm, use --compress option:
$ xtrabackup --backup --compress --target-dir=/data/backup
lz4
To compress files using the lz4 compression algorithm, set --compress option to lz4:
$ xtrabackup --backup --compress=lz4 --target-dir=/data/backup
Zstandard (ZSTD)
The Zstandard (ZSTD) compression algorithm is a tech preview feature. Before using ZSTD in production, we recommend that you test restoring production from physical backups in your environment, and also use the alternative backup method for redundancy.
Percona XtraBackup 8.0.30-23 adds support for the Zstandard (ZSTD) compression algorithm. ZSTD is a fast lossless compression algorithm that targets real-time compression scenarios and better compression ratios.
To compress files using the ZSTD compression algorithm, set --compress option to zstd:
$ xtrabackup --backup --compress=zstd --target-dir=/data/backup
You can specify ZSTD compression level with the --compress-zstd-level(=#) option. The default value is 1.
$ xtrabackup --backup --compress-zstd-level=1 --target-dir=/data/backup
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/
Expected output
...
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!
Prepare 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/
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.
Restore 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:
Expected output
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.
