WALMGR(1)																 WALMGR(1)

NAME

       walmgr - tools for managing WAL-based replication for PostgreSQL.

SYNOPSIS

       walmgr.py <config.ini> command

DESCRIPTION

       It is both admin and worker script for PostgreSQL PITR replication.

QUICK START

	1. Set up passwordless ssh authentication from master to slave

	       master$ test -f ~/.ssh/id_dsa.pub || ssh-keygen -t dsa
	       master$ cat ~/.ssh/id_dsa.pub | ssh slave cat >> .ssh/authorized_keys

	2. Configure paths

	       master$ edit master.ini
	       slave$ edit slave.ini

	       Make sure that walmgr.py executable has same pathname on slave and master.

	3. Start archival process and create a base backup

	       master$ ./walmgr.py master.ini setup
	       master$ ./walmgr.py master.ini backup

	       Note: starting from PostgreSQL 8.3 the archiving is enabled by setting
	       archive_mode GUC to on. However changing this parameter requires the
	       server to be restarted.

	4. Prepare postgresql.conf and pg_hba.conf on slave and start replay

	       master$ scp $PGDATA/*.conf slave:
	       slave$ ./walmgr.py slave.ini restore

	       For debian based distributions the standard configuration files are located
	       in /etc/postgresql/x.x/main directory. If another scheme is used the postgresql.conf
	       and pg_hba.conf should be copied to slave full_backup directory. Make sure to
	       disable archive_command in slave config.

	       'walmgr.py restore' moves data in place, creates recovery.conf and starts postmaster
	       in recovery mode.

	5. In-progress WAL segments can be backup by command:

	       master$ ./walmgr.py master.ini sync

	6. If need to stop replay on slave and boot into normal mode, do:

	       slave$ ./walmgr.py slave.ini boot

GENERAL OPTIONS

       Common options to all walmgr.py commands.

       -h, --help
	   show this help message and exit

       -q, --quiet
	   make program silent

       -v, --verbose
	   make program more verbose

       -n, --not-really
	   Show what would be done without actually doing anything.

MASTER COMMANDS

   setup
       Sets up postgres archiving, creates necessary directory structures on slave.

   sync
       Synchronizes in-progress WAL files to slave.

   syncdaemon
       Start WAL synchronization in daemon mode. This will start periodically synching the in-progress WAL files to slave.

       The following parameters are used to drive the syncdaemon: loop_delay - how long to sleep between the synchs. use_xlog_functions - use
       record based shipping to synchronize in-progress WAL segments.

   stop
       Deconfigures postgres archiving.

   periodic
       Runs periodic command, if configured. This enables to execute arbitrary commands on interval, useful for synchronizing scripts, config
       files, crontabs etc.

   listbackups
       List backup sets available on slave node.

   backup
       Creates a new base backup from master database. Will purge expired backups and WAL files on slave if keep_backups is specified. During a
       backup a lock file is created in slave completed_wals directory. This is to prevent simultaneous backups and resulting corruption. If
       running backup is terminated, the BACKUPLOCK file may have to be removed manually.

   restore <set> <dst>
       EXPERIMENTAL. Attempts to restore the backup from slave to master.

SLAVE COMMANDS

   boot
       Stop log playback and bring the database up.

   pause
       Pauses WAL playback.

   continue
       Continues previously paused WAL playback.

   listbackups
       Lists available backups.

   backup
       EXPERIMENTAL. Creates a new backup from slave data. Log replay is paused, slave data directory is backed up to full_backup directory and
       log replay resumed. Backups are rotated as needed. The idea is to move the backup load away from production node. Usable from postgres 8.2
       and up.

   restore [src][dst]
       Restores the specified backup set to target directory. If specified without arguments the latest backup is moved to slave data directory
       (doesn't obey retention rules). If src backup is specified the backup is copied (instead of moving). Alternative destination directory can
       be specified with dst.

CONFIGURATION

   Common settings
       job_name
	   Optional. Indentifies this script, used in logging. Keep unique if using central logging.

       logfile
	   Where to log.

       use_skylog
	   Optional. If nonzero, skylog.ini is used for log configuration.

   Master settings
       pidfile
	   Pid file location for syncdaemon mode (if running with -d). Otherwise not required.

       master_db
	   Database to connect to for pg_start_backup() etc. It is not a good idea to use dbname=template if running syncdaemon in record shipping
	   mode.

       master_data
	   Master data directory location.

       master_config
	   Master postgresql.conf file location. This is where archive_command gets updated.

       master_restart_cmd
	   The command to restart master database, this used after changing archive_mode parameter. Leave unset, if you cannot afford to restart
	   the database at setup/stop.

       slave
	   Slave host and base directory.

       slave_config
	   Configuration file location for the slave walmgr.

       completed_wals
	   Slave directory where archived WAL files are copied.

       partial_wals
	   Slave directory where incomplete WAL files are stored.

       full_backup
	   Slave directory where full backups are stored.

       config_backup
	   Slave directory where configuration file backups are stored. Optional.

       loop_delay
	   The frequency of syncdaemon updates. In record shipping mode only incremental updates are sent, so smaller interval can be used.

       use_xlog_functions
	   Use pg_xlog functions for record based shipping (available in 8.2 and up).

       compression
	   If nonzero, a -z flag is added to rsync cmdline. Will reduce network traffic at the cost of extra CPU time.

       periodic_command
	   Shell script to be executed at specified time interval. Can be used for synchronizing scripts, config files etc.

       command_interval
	   How ofter to run periodic command script. In seconds, and only evaluated at log switch times.

       hot_standby ===
	   Boolean. If set to true, walmgr setup will set wal_level to hot_standby (9.0 and newer).

   Sample master.ini
	   [wal-master]
	   logfile		= master.log
	   pidfile		= master.pid
	   master_db		= dbname=template1
	   master_data		= /var/lib/postgresql/8.0/main
	   master_config	= /etc/postgresql/8.0/main/postgresql.conf
	   slave		= slave:/var/lib/postgresql/walshipping
	   completed_wals	= %(slave)s/logs.complete
	   partial_wals 	= %(slave)s/logs.partial
	   full_backup		= %(slave)s/data.master
	   loop_delay		= 10.0
	   use_xlog_functions	= 1
	   compression		= 1

   Slave settings
       slave_data
	   Postgres data directory for the slave. This is where the restored backup is copied/moved.

       slave_config_dir
	   Directory for postgres configuration files. If specified, "walmgr restore" attempts to restore configuration files from config_backup
	   directory.

       slave_stop_cmd
	   Script to stop postmaster on slave.

       slave_start_cmd
	   Script to start postmaster on slave.

       slave
	   Base directory for slave files (logs.complete, data.master etc)

       slave_bin
	   Specifies the location of postgres binaries (pg_controldata, etc). Needed if they are not already in the PATH.

       completed_wals
	   Directory where complete WAL files are stored. Also miscellaneous control files are created in this directory (BACKUPLOCK, STOP, PAUSE,
	   etc.).

       partial_wals
	   Directory where partial WAL files are stored.

       full_backup
	   Directory where full backups are stored.

       keep_backups
	   Number of backups to keep. Also all WAL files needed to bring earliest

	   backup up to date are kept. The backups are rotated before new backup is started, so at one point there is actually one less backup
	   available.

	   It probably doesn't make sense to specify keep_backups if periodic backups are not performed - the WAL files will pile up quickly.

	   Backups will be named data.master, data.master.0, data.master.1 etc.

       archive_command
	   Script to execute before rotating away the oldest backup. If it fails backups will not be rotated.

       slave_pg_xlog
	   Set slave_pg_xlog to the directory on the slave where pg_xlog files get written to. On a restore to the slave walmgr.py will create a
	   symbolic link from data/pg_xlog to this location.

       backup_datadir
	   Set backup_datadir to no to prevent walmgr.py from making a backup of the data directory when restoring to the slave. This defaults to
	   yes

   Sample slave.ini
	   [wal-slave]
	   logfile		= slave.log
	   slave_data		= /var/lib/postgresql/8.0/main
	   slave_stop_cmd	= /etc/init.d/postgresql-8.0 stop
	   slave_start_cmd	= /etc/init.d/postgresql-8.0 start
	   slave		= /var/lib/postgresql/walshipping
	   completed_wals	= %(slave)s/logs.complete
	   partial_wals 	= %(slave)s/logs.partial
	   full_backup		= %(slave)s/data.master
	   keep_backups 	= 5
	   backup_datadir	= yes

								    03/13/2012								 WALMGR(1)