table of contents
AMPGSQL(8) | System Administration Commands | AMPGSQL(8) |
NAME¶
ampgsql - Amanda Application to interface with PostgreSQLDESCRIPTION¶
Ampgsql is an Amanda Application API script. It should not be run by users directly. It implements on-line backups of PostgreSQL databases in conjunction with WAL archiving.DISKLIST¶
The diskdevice must be the cluster data directory, if it is "/var/lib/pgsql/data":HOST DISKNAME /var/lib/pgsql/data DUMPTYPE or HOST /var/lib/pgsql/data DUMTYPE
OPERATION¶
This application implements the backup strategy described in http://www.postgresql.org/docs/current/static/continuous-archiving.html. For a level zero (full) backup, ampgsql:•execute PG_START_BACKUP()
•dump the data directory
•execute PG_STOP_BACKUP()
•wait for the final WAL file to be archived
•back up the required WAL files
•optionally delete WAL files that are no longer
necessary
The two dumps are made with GNU Tar, to data_dir.tar and archive_dir,
respectively. They are then combined into a single tar file.
A level N backup creates a single tar file containing all WAL files since the
previous level N-1 backup.
PROPERTIES¶
This section lists the amanda.conf(5) properties that control ampsql's functionality. See amanda-applications(7) for information on application properties and how they are configured. ARCHIVEDIRDirectory that WAL segment files are archived to, as
specified by the archive_command in PosgreSQL's postgresql.conf. The amanda
user on the client must have at least read and execute permission on this
directory, and preferably write. Without write permission, Amanda cannot clean
up expired WAL and backup files.
CLEANUPWAL
Whether or not to remove old WAL segment files during
base backups. Defaults to yes.
DB
Database to connect to. Defaults to "template1"
(which exists by default).
DIRECTORY
For restore command only, the data is recoved in that
directory. Must be a unix path.
GNUTAR-PATH
Path to the GNU tar executable. This option only has an
effect during restore. The default is set when Amanda is built by the
--with-gnutar configure option.
HOST
Host to connect to. If it starts with "/" it
will be interepreted as a directory that holds the socket file. PostgreSQL
defaults to /tmp.
MAX-WAL-WAIT
The maximum amount of time to wait for PG_STOP_BACKUP to
archive a WAL file. In versions of PostgreSQL before 8.2, PG_STOP_BACKUP does
not automatically archive the latest WAL file, so a quiet database may wait a
very long time before archiving the WAL file. Default: 60 seconds. Set to 0 to
wait forever.
PASSFILE
Connect using the creditials in this file. Each line
should have the format "hostname:port:database:username:password".
The permissions must permit it to be read only by the user, or the file will
not be used. Only usable with Postgres 8.1 and up.
PORT
The TCP port to connect to, or the suffix of the socket
file. PostgreSQL defaults to 5432.
PSQL-PATH
Path to the psql binary. If not specified, the PATH
environment variable will be searched.
STATEDIR
Directory for saving state about backups already made.
The default is set when Amanda is built by the --with-gnutar-listdir configure
option.
TMPDIR
Directory to use for temporary files during the backup
process. It should have enough space to store a complete copy of the database.
The default is set when Amanda is built by the --with-tmpdir configure
option.
USER
User to connect as. It must be a superuser.
VERBOSE
Do not use the --quiet output of psql.
CLIENT PROPERTIES¶
Client properties are deprecated. All properties should be set in the dumptype. This section lists the amanda-client.conf(5) properties that control ampsql's functionality. If a property is prefixed with the diskname and an underscore, then it will be used when that diskname is being backed up. For example, if the properties PG-DATADIR and foo-PG-DATADIR are set, the value of PG-DATADIR will be used when bar and baz are being backed up, but foo-PG-DATADIR will be used when foo is being backed up. Disknames are specified in the disklist(5). PG-ARCHIVEDIR
Directory that WAL segment files are archived to, as specified by the
archive_command in PosgreSQL's postgresql.conf. The amanda user on the client
must have at least read and execute permission on this directory, and
preferably write. Without write permission, Amanda cannot clean up expired WAL
and backup files.
PG-CLEANUPWAL
Whether or not to remove old WAL segment files during base backups. Defaults to
yes.
PG-DATADIR
Cluster data directory
PG-DB
Database to connect to. Defaults to "template1" (which exists by
default).
PG-HOST
Host to connect to. If it starts with "/" it will be interepreted as a
directory that holds the socket file. PostgreSQL defaults to /tmp.
PG-MAX-WAL-WAIT
The maximum amount of time to wait for PG_STOP_BACKUP to
archive a WAL file. In versions of PostgreSQL before 8.2, PG_STOP_BACKUP does
not automatically archive the latest WAL file, so a quiet database may wait a
very long time before archiving the WAL file. Default: 60 seconds. Set to 0 to
wait forever.
PG-PASSFILE
Connect using the creditials in this file. Each line should have the format
"hostname:port:database:username:password". The permissions must
permit it to be read only by the user, or the file will not be used. Only
usable with Postgres 8.1 and up.
PG-PASSWORD
Password to use when connecting. Deprecated in favor of passfiles.
PG-PORT
The TCP port to connect to, or the suffix of the socket file. PostgreSQL
defaults to 5432.
PG-USER
User to connect as. It must be a superuser.
PSQL-PATH
Path to the psql binary. If not specified, the PATH environment variable will be
searched.
RECOVERY¶
Read the postgres documentation carefully before attempting a recovery. This section is only a rough guide to the process. The data recovered from a postgres backup consists of a data tarball and one or more archive tarballs. The data contains the state of the database at the time the full backup was performed, and the archive tarballs contain postgres WAL files that must be re-run to generate a consistent state. Ensure that the database server is shut down, and move the existing data directory aside. Untar the data tarball over this directory, and verify that ownership and permissions are correct. Untar all of the archive tarballs into a single directory - the archive directory. Create a recovery.conf in the data directory, owned by the proper user and with proper permissions. Add a restore_command to it, e.g.,restore_command = 'cp /path/to/archive_dir/%f "%p"'Start the database server, and examine the logs to track the process of the recovery. When the recovery is complete, the server will transition into a running state, and will move the recovery.conf file aside so that it will not attempt a recovery on the next invocation.
EXAMPLE¶
In amanda.conf:define application app_ampgsql { plugin "ampgsql" property "HOST" "localhost" property "ARCHIVEDIR" "/tmp/archivedir" property "PASSFILE" "/etc/amanda/ampgsql.passwd" } define dumptype dump_ampgsql { global program "APPLICATION" application app_ampgsql }The disklist file:
localhost /var/lib/pgsql/data dump_ampgsql or localhost postgres /var/lib/pgsql/data dump_ampgsql
SEE ALSO¶
amanda(8), amanda.conf(5), amanda-client.conf(5), amanda-applications(7) The Amanda Wiki: : http://wiki.zmanda.com/AUTHOR¶
Nikolas Coukouma <atrus@zmanda.com>Zmanda, Inc. (http://www.zmanda.com)
07/11/2014 | Amanda 3.3.6 |