Replication and External Data - PostgreSQL: Up and Running - page 183

archive_command = 'copy %p ..\\archive\\%f'
4. The pg_hba.conf file should include a rule allowing the slaves to act as replication
agents. As an example, the following rule will allow a PostgreSQL account named
pgrepuser on a server on my private network with an IP address in the range
192.168.0.1 to 192.168.0.254 to replicate using an md5 password:
host replication pgrepuser 192.168.0.0/24 md5
5. Shut down the PostgreSQL service and copy all the files in the data folder except
the pg_xlog and pg_log folders to the slaves. Make sure that pg_xlog and pg_log
folders are both present on the slaves but devoid of any files.
If you have a large database cluster and can't afford a shutdown for the duration of
the copy, you can use the pg_basebackup utility, found in the bin folder of your
PostgreSQL installation. This will create a copy of the data cluster files in the speci‐
fied directory and allow you to do a base backup while the postgres service is
running.
Configuring the Slaves
To minimize headaches, slaves should have the same configuration as the master, es‐
pecially if you'll be using them for failover. In order for the server to be a slave, it must
be able to play back the WAL transactions of the master. The steps for creating a slave
are:
1. Create a new instance of PostgreSQL with the same version (preferably even mi‐
croversions) as your master server and the same OS at the same patch level. Keeping
servers identical is not a requirement, and you're welcome to experiment and see
how far you can deviate.
2. Shut down PostgreSQL on the new slave.
3. Overwrite the data folder files with those you copied from the master.
4. Add the following configuration setting to the postgresql.conf file:
hot_standby = on
5. You don't need to run the slaves on the same port as the master, so you can optionally
change the port either via postgresql.conf or via some other OS-specific startup script
that sets the PGPORT environment variable before startup. Any startup script will
override the setting you have in postgresql.conf .
6. Create a new file in the data folder called recovery.conf that contains the following
lines, and substitute the actual host name, IP address, and port of your master on
the second line:
standby_mode = 'on'
primary_conninfo = 'host=192.168.0.1 port=5432 user=pgrepuser password=woo-