| title | section | header | footer | author | date | adjusting | hyphenate | Generate | |
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mysql-backup |
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User manual |
mysql-backup |
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2022-10-19 19:15:56 -0700 |
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pandoc -s -f markdown-smart -t man mysql-backup.1.md -o mysql-backup.1 |
mysql-backup - Backup MySQL databases.
mysql-backup [ options ] [ --dump | --snapshot | --check ]
mysql-backup performs daily, weekly and monthly backup of MySQL databases. Features:
- Backup multiple databases
- Compress backup files
- Backup remote servers
- Rotate backups
- more...
-c CONFIG, --config CONFIG : A configuration file to use instead of default one. This option allows different configuration for different MySQL servers.
-v, verbose : Run in verbose mode.
-h, --help : Show a short help screen.
--dry-run : Run in dry-run mode, do not perform any action.
--dump, -d : Do a mysqldump backup.
--snapshot, -s : Perform a binary backup using lvm or zfs snapshot.
--check, -C : Do a nagios comptatible check (See MONITORING below).
NOTE: To restore a LVM or ZFS snapshot you just need to untar the archive.
mysql-backup looks for a default configuration file in that order:
/etc/mysql-backup/default.cnf~/.mysql-backup.cnf./.mysql-backup.cnf
If no default configuration file is found, default hard-coded values would be used.
In addition of the default configuration, a specific configuration file can
be used (with the --conf option).
BACKUP_DIR : Where the backups files would be stored. A generic backup file schema is:
\<BACKUP_DIR>/\<host>/\<binary|dump>/\<daily|weekly|monthly>/\<base>_YYYY-MM-DD.sql[.\<COMPRESSION_EXTENSION>]
DATABASES : Databases to backup. If this value is set to ALL then all databases would be backuped. mysql-backup would determine the database using the "SHOW DATABASES" query.
IGNORE_DATABASES : A list of database to ignore during backup. By default, information_schema and performance_schema are ignored.
In addition to that option all mysql(1) and mysqldump(1) options are also
recognized as long as dash (-) are changed to underscore (_).
NOTE: However some options are not recognized: help, pipe, table, version, databases, ignore-table, ssl, execute.
EXAMPLE: This is the default MySQL configuration:
batch=1
skip_column_names=1
quote_names=1
opt=1
add_drop_database=1
EXAMPLE: If you use mysqld_multi you can defined a common complex configuration file (ie. /etc/mysql-backup/__multi-defaults.inc) such as:
BACKUP_DIR=/var/backups/mysql/
HOST=articles${_instance}
TARGET_MOUNT=/tmp/$HOST-bck
LVM_SNAPSHOT_SIZE="100G"
mysql_instance=mysqld${_instance}
proto=SOCKET
socket=/var/run/mysqld/mysqld_${_instance}.sock
tar_opts=""
mysqladmin_extra_file=/etc/mysql/debian_${_instance}.cnf
user=$(${my_print_defaults} -c ${mysqladmin_extra_file} client | awk -F= '{if($1~/^--user$/){print $2}}')
password=$(${my_print_defaults} -c ${mysqladmin_extra_file} client | awk -F= '{if($1~/^--password$/){print $2}}')
and an instance specific configuration in (/etc/mysql-backup/instance00.cnf):
instance=00
source /etc/mysql-backup/__multi-defaults.inc
And a cron such as:
01 00 * * * root mysql-backup -c /etc/mysql-backup/instance00.cnf --snapshot
SUFFIX : Suffix to datadir_path when creating a snapshot backup. You can safely leave it empty if you are using default mysql configuration. If you are using your own layout you should use this option.
EXAMPLE: If your layout is something like that:
/var/lib/mysql/db_00
|-- binlog
|-- config
| |-- conf.d
| | `-- mysql-multi.cnf
| |-- debian.cnf
| |-- my.cnf
| `-- mysql-backup.cnf
|-- data
| |-- aria_log.00000001
| |-- aria_log_control
| |-- mysql
| |-- relay-log.info
| |-- show-master-status
| `-- show-slave-status
|-- log
|-- mysql-multi.txt
`-- tmp
datadir_path is pointing to /var/lib/mysql/db_00/data but you also want to backup other files so you have to set SUFFIX to ...
MYSQL_PING_TIMEOUT : Startup time given to mysql before declaring it non-functional (default 600s). This is used when starting mysql in the temporary directory before creating the archive.
COMPRESSION : The tool to use for compression. Currently gzip, pigz, bzip2 and xz are recognized. If compression if not known then no compression would be used.
NOTE: gzip generates bigger files than the others but needs less CPU time.
COMPRESSION_OPTS : Options to pass to the compression tool.
DAILY_RETENTION : How many days a daily backup should be kept. By default daily archives are kept 7 days.
WEEKLY_RETENTION : How many days a weekly backup should be kept. By default weekly archives are kept 35 days (5 weeks).
MONTHLY_RETENTION : How many days a monthly backup should be kept. By default monthly archives are kept 365 days (12 months).
WEEKLY_DAY : Which day weekly backup are done (0..6, 0 is Sunday).
MONTHLY_DAY : Which day monthly backup are done (00..31).
HOST : Name of the host to backup for logging purposes.
NOTE: This is not the mysql host to backup (use "host" in lowercase for that).
LVM_EXT : Extension for the LVM snapshot (Default: "_bkp") that would be added to the current LVM volume name.
LVCREATE_OPTS : Options to pass to lvcreate(1) when doing LVM snapshot (Default: "--chunksize=256").
LVREMOVE_OPTS : Options to pass to lvremove(1) when purging a snapshot (Default: "-f").
TARGET_MOUNT : Where to mount the LVM snapshot before archiving the data (Default: "/tmp/mysql-snapshot").
There are no ZFS option. mysql-backup use ZFS by default if it detects mysql is running on a ZFS volume.
Hooks are scripts that can be run via run-parts(8). Each hook parameter consists of a directory path suitable for run-parts(8).
See run-parts(8) for further information on how hooks are run.
See HOOK DETAILS section for details.
Every day backups are done in the daily directory. On WEEKLY_DAY the daily backup is hard linked to the weekly directory (the same is done for monthly backups on MONTHLY_DAY and monthly directory).
After that archives older that DAILY_RETENTION, WEEKLY_RETENTION and MONTHLY_RETENTION are removed from their specific directories.
This system keeps space on the backup server by the use of hard links.
NOTE: This only works if all backups are in a single partition.
First mysql-backup generate a LVM snapshot of the mysql you want to backup. During that snapshot creation the replication is stopped, the tables are locked ("FLUSH TABLES WITH READ LOCK"). Then the current replication status (for both master and slave) are dumped into mysql datadir in files show-master-status and show-slave-status.
For each kind of backup (snapshot or dump) an other mysqld instance is started using the new lvm snapshot as datadir. This will ensure the rebuild of innodb journal and indexes. Then the archive process is run (mysqldump for dump and tar for snapshot).
NOTE: For big databases you'd better want to use a snapshot backup since the archive process would be faster and the restoration either.
Once every backup are done, the lvm/zfs snapshot is removed.
For better performances, it is advised to run mysql-backup on a dedicated backup server instead of production, especially if you are using pigs(1).
ZFS offers better performances than LVM. You might also want to use the ZFS compression features to drastically reduce the IOs.
As an example backing up 10 mysql database representing about 760Gb took almost one day using LVM. The server had a lot of harddrive IOwait. The very same hardware was used to perform backups on ZFS volumes using compression allowed to raise the mysql instances to 24. The hard drive usage drops to 250Gb thanks to ZFS compression. The whole backup process took less than 2 hours.
On the mysql-backup instances you also want to totally disable binary
logs. Use skip_log_bin=1 and log_slave_update=0 for that purpose.
If you are using pigz(1) avoid running several backups in parallel.
For binary snapshot you only need to untar the archive on a new server to create a clone.
For dump backups, you need to replay every database files, such as:
zcat base_YYY-MM-DD.sql.gz | mysql -
pre_dump_backup_hook : Hook to be run before the dump backup process really starts.
post_dump_backup_hook : Hook to be run after the dump backup process is done.
pre_dump_restore_hook : Hook to be run before the dump restore process really starts.
post_dump_restore_hook : Hook to be run after the dump restore process is done.
NOTE: In addition hook names could be postfixed with a database name. This means a hook could be defined for a specific database.
EXAMPLE: post_dump_backup_hook_a_database is ran before a_database would be backuped.
pre_snapshot_backup_hook : Hook to be run before a snapshot really stats.
post_snapshot_backup_hook : Hook to be run when a snapshot is done.
pre_snapshot_backup_lvm_snaphost_hook : Hook to be run before the LVM snapshot is started.
post_snapshot_backup_lvm_snaphost_hook : Hook to be run after the LVM snapshot is done.
pre_snapshot_backup_zfs_snaphost_hook : Hook to be run before the ZFS snapshot is started.
post_snapshot_backup_zfs_snaphost_hook : Hook to be run after the ZFS snapshot is done.
pre_snapshot_backup_archive_hook : Hook to be run before the archive process is started.
post_snapshot_backup_archive_hook : Hook to be run after the archive process is done.
NOTE: There is no database postfix for snapshot hooks since there would be nonsense.
Performing a nagios-like check allow to make sure that backups are done regulary. For this purpose it will test if the lock file is neither present nor older than 24h and check if the last backup is not older than 24h. Those values are hardcoded because in most of cases it makes no sense to do eithe more or less than one backup per day.
If you are using NRPE (allowing arguments) you can add this in you configuration file:
command[check_mysql_backup] = sudo /usr/local/bin/mysql-backup --check -c $ARG1$
If you don't allow arguments you need to define one check per backup instance.
Do not forget the sudo line:
nagios ALL=(mysql) NOPASSWD:/usr/local/bin/mysql-backup --check -c *
- mysql(1)
- mysqldump(1)
- gzip(1), bzip2(1), xz(1), pigz(1)
- run-parts(8)
2022-10-20:
- Migrate help as comment
- Do not run atexit is help is displayed
2019-01-04:
- Add ZFS support
- Add PID to log entries.
- Enhance log messages.
- Enhance launch of temporary mysql instance.
- Add support for pigz.
- Add SUFFIX option for multi-instance mysql backup.
2015-02-02:
- Wait if blocked queries are longer than 10s.
2014-03-06:
- rewrite the core application.
- bump to version 2.0
2012-06-04:
- Add replication information for dumps
- Add snapshot option
- Add LVCREATE_OPTS
2010-09-06:
First release.
No time to include bugs, command actions might seldom lead astray user's assumption.
Copyright © 2010-2017 Sébastien Gross <seb•ɑƬ•chezwam•ɖɵʈ•org>.
Released under GNU GPL version 3 or higher.