NAME

       walmgr3 - tool for managing WAL-based replication for PostgreSQL.

SYNOPSIS

       walmgr3 <config.ini> command [--not-really] [options]

DESCRIPTION

       Walmgr3 is a tool to handle replication of PostgreSQL with PITR (also known as Log
       Shipping).

       This script allows to setup and administer the replication, it is also used by PostgreSQL
       to archive and restore the WAL files.

       See QUICK START below to start your first log shipping in few steps.

       The command is one of the Master, Slave, Common or Internal commands listed below.

GENERAL OPTIONS

       -V, --version
           Print version info and exit.

       -h, --help
           Show this help message and exit.

       -q, --quiet
           Log only errors and warnings.

       -v, --verbose
           Log verbosely.

       -d, --daemon
           Run in daemon mode (go background).

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

SPECIFIC OPTIONS

       --ini
           Display sample ini file.

       --set="param=val[,param=value]"
           Override config setting

       --init-master
           Initialize Master walmgr3 configuration.

       --init-slave
           Initialize Slave walmgr3 configuration.

       --config-dir=filepath
           Configuration file location for --init-X commands.

       --slave=hostname
           Slave host name.

       --pgdata=path
           PostgreSQL data directory.

       --ssh-keygen
           Generate a SSH key pair if needed (used in Master).

       --ssh-add-key=keyfile.pub
           Add the public key file to authorized_hosts file (used in Slave).

       --ssh-remove-key=ssh_key
           Remove Master ssh key from authorized_hosts file (used in Slave).

       --primary-conninfo=connection_string
           Provide the connection string to the streaming replication Master (used in Slave).

       --add-password=plaintext_file
           Add password for streaming replication from plain text file to .pgpass. Additional
           fields for password file entry will be extracted from primary-conninfo (used in
           Slave).

       --remove-password
           Remove .pgpass entry, which was used for streaming replication (used in Slave)

       --synch-standby=synchronous_standby_names
           Do the same thing as command synch-standby, but walmgr ini file is not used. This
           option can be used when walmgr ini is not available. It tries to guess the postgres
           config location, --pgdata option may also be needed. (used in Master)

DAEMON OPTIONS

       -r, --reload
           Reload config (send SIGHUP).

       -s, --stop
           Stop program safely (send SIGINT).

       -k, --kill
           Kill program immediately (send SIGTERM).

MASTER COMMANDS

   setup
       Sets up PostgreSQL for WAL archiving, creates necessary directory structures on Slave.

   sync
       Copies 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 configuration 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
       Stop archiving and de-configure PostgreSQL archiving.

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

   synch-standby
       Enables/disables synchronous streaming replication for given application name(s). Does
       additional check before enabling synchronous mode.

SLAVE COMMANDS

   boot
       Stop WAL playback and bring the database up so it can accept queries.

   pause
       Pauses WAL playback.

   continue
       Continues previously paused WAL playback.

   createslave
       Creates backup from Master database using streaming replication. Also creates
       recovery.conf and starts slave standby. Backup is created with pg_basebackup and
       pg_receivexlog (available in 9.2 and up).

COMMON COMMANDS

   listbackups
       Lists available backups 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 not 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.

       EXPERIMENTAL: If run on Slave, creates backup from in-recovery Slave data. WAL playback is
       paused, Slave data directory is backed up to full_backup directory and WAL playback is
       resumed. Backups are rotated as needed. The idea is to move the backup load away from
       production node. Usable from PostgreSQL 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 moved). Alternative destination
       directory can be specified with dst.

   cleanup
       Cleanup any walmgr3 files after stop.

INTERNAL COMMANDS

   xarchive <srcpath> <srcname>
       On Master, archive one WAL file.

   xrestore <srcname> <dstpath> [last restartpoint wal]
       On Slave, restore one WAL file.

   xlock
       On Master, create lock file to deny other concurrent backups.

   xrelease
       On Slave, remove backup lock file, allow other backup to run.

   xrotate
       Rotate backups by increasing backup directory suffixes. Note that since we also have to
       make room for next backup, we actually have keep_backups - 1 backups available after this.

       Unneeded WAL files are not removed here, it is handled by xpurgewals command instead.

   xpurgewals
       On Slave, remove WAL files not needed for recovery.

   xpartialsync <filename> <offset> <bytes>
       Read bytes worth of data from stdin, append to the partial WAl file starting from offset.
       On error it is assumed that master restarts from zero.

       The resulting file is always padded to XLOG_SEGMENT_SIZE bytes to simplify recovery.

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 walmgr3.

       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
           Optional. Slave directory where configuration file backups are stored.

       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. It reduces network traffic at the
           cost of extra CPU time.

       keep_symlinks
           Keep symlinks for pg_xlog and pg_log.

       hot_standby
           If set to 1, walmgr3 setup will set wal_level to hot_standby (PostgreSQL 9.0 and
           newer).

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

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

   Sample master.ini
           [walmgr]
           job_name             = wal-master
           logfile              = ~/log/%(job_name)s.log
           pidfile              = ~/pid/%(job_name)s.pid
           use_skylog           = 1

           master_db            = dbname=my_db
           master_data          = /var/lib/postgresql/9.1/main
           master_config        = /etc/postgresql/9.1/main/postgresql.conf
           master_bin           = /usr/lib/postgresql/9.1/bin

           # set this only if you can afford database restarts during setup and stop.
           #master_restart_cmd   = /etc/init.d/postgresql-9.1 restart

           slave = slave-host
           slave_config = /var/lib/postgresql/conf/wal-slave.ini

           walmgr_data          = /var/lib/postgresql/walshipping
           completed_wals       = %(walmgr_data)s/logs.complete
           partial_wals         = %(walmgr_data)s/logs.partial
           full_backup          = %(walmgr_data)s/data.master
           config_backup        = %(walmgr_data)s/config.backup

           # syncdaemon update frequency
           loop_delay           = 10.0
           # use record based shipping available since 8.2
           use_xlog_functions   = 0

           # pass -z to rsync, useful on low bandwidth links
           compression          = 0

           # keep symlinks for pg_xlog and pg_log
           keep_symlinks        = 1

           # tell walmgr to set wal_level to hot_standby during setup
           #hot_standby = 1

           # periodic sync
           #command_interval     = 600
           #periodic_command     = /var/lib/postgresql/walshipping/periodic.sh

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

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

       slave_stop_cmd
           Script to stop PostgreSQL on Slave.

       slave_start_cmd
           Script to start PostgreSQL on Slave.

       slave_config_dir
           Directory for PostgreSQL configuration files. If specified, walmgr3 restore attempts
           to restore configuration files from config_backup directory.

       slave_pg_xlog
           Set to the directory on the Slave where pg_xlog files get written to. On a restore to
           the Slave walmgr3 will create a symbolic link from data/pg_xlog to this location.

       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.

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

       backup_datadir
           Set backup_datadir to no to prevent walmgr3 from making a backup of the data directory
           when restoring to the Slave. This defaults to yes.

       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.

       primary_conninfo
           Primary database connection string for hot standby - enabling this will cause the
           Slave to be started in hot standby mode.

   Sample slave.ini
           [walmgr]
           job_name             = wal-slave
           logfile              = ~/log/%(job_name)s.log
           use_skylog           = 1

           slave_data           = /var/lib/postgresql/9.1/main
           slave_bin            = /usr/lib/postgresql/9.1/bin
           slave_stop_cmd       = /etc/init.d/postgresql-9.1 stop
           slave_start_cmd      = /etc/init.d/postgresql-9.1 start
           slave_config_dir     = /etc/postgresql/9.1/main

           # alternative pg_xlog directory for slave, symlinked to  pg_xlog on restore
           #slave_pg_xlog        = /vol2/pg_xlog

           walmgr_data          = ~/walshipping
           completed_wals       = %(walmgr_data)s/logs.complete
           partial_wals         = %(walmgr_data)s/logs.partial
           full_backup          = %(walmgr_data)s/data.master
           config_backup        = %(walmgr_data)s/config.backup

           backup_datadir       = yes
           keep_backups         = 0
           archive_command =

           # primary database connect string for hot standby -- enabling
           # this will cause the slave to be started in hot standby mode.
           #primary_conninfo = host=master port=5432 user=postgres

EXIT STATUS

       0
           Successful program execution.

ENVIRONMENT

       PostgreSQL environment variables can be used.

QUICK START

        1. Set up passwordless ssh-key on Master and write configuration file

               master$ walmgr3 --ssh-keygen --init-master --slave <slave_hostname>

        2. Set up passwordless ssh authentication from Master to Slave and write configuration
           file on Slave

               slave$ walmgr3 --init-slave --ssh-add-key=/tmp/id_rsa.pub

        3. Logging setup on Master and Slave

               master$ cp skylog.ini ~postgres/
               slave$ cp skylog.ini ~postgres/

        4. Start archival process and create a base backup

               master$ walmgr3 /var/lib/postgresql/conf/wal-master.ini setup
               master$ walmgr3 /var/lib/postgresql/conf/wal-master.ini backup

               CAUTION: 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.

        5. Prepare postgresql.conf and pg_hba.conf on Slave and start replay

               slave$ walmgr3 /var/lib/postgresql/conf/wal-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.

               'walmgr3 restore' moves data in place, creates recovery.conf and
               starts postmaster in recovery mode.

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

               master$ walmgr3 /var/lib/postgresql/conf/wal-master.ini sync

        7. If need to stop replay on Slave and boot into normal mode, do:

               slave$ walmgr3 /var/lib/postgresql/conf/wal-slave.ini boot

                                            06/14/2018                                 WALMGR3(1)