1. 环境规划

Primary和Standby节点最好有相同的环境。

2. 安装PostgreSQL

1）在Primary和Standy节点上安装PostgreSQL软件，安装路径为/opt/pgsql

2）设置postgres用户的环境变量

     PGHOME=/opt/pgsql

     PGDATA=/home/postgres/main

     PATH=$PG_HOME/bin:$PATH:$HOME/bin

3. Primary节点

1）切换到postgres用户

$su - postgres

2）初始化数据库

$initdb

3）配置pg_hba.conf

在# IPv4 local connections下面添加一行，设置PostgreSQL的访问及其权限

host all all 192.168.0.1/24 trust

在# replication privilege.下面添加一行，设置replication用户及权限

host replication postgres 192.168.0.1/24 trust

4）配置postgresql.conf

配置监听，修改listen_addresses = 'localhost'

listen_addresses = '*' # what IP address(es) to listen on;

配置Primary Replication参数

     wal_level = hot_standby

     max_wal_senders = 8

     wal_keep_segments = 32

     archive_mode = on

     archive_command = 'cp %p /home/postgres/archive/%f < /dev/null'

"/home/postgres/archive"是Replication的archive的存储路径。PostgreSQL会将Replication的WAL保存在 "/home/postgres/archive"路径下。

5) 启动Primary上的PostgreSQL数据库

$pg_ctl start

6) 在primary上执行以下命令

$psql -c "SELECT pg_start_backup('label', true);"

将Primary的PGDATA目录下的文件，除了postmaster.pid复制到Standby节点的“/home/postgres/main”目录下，该目录是 Standby节点上的PostgreSQL数据库的PGDATA目录。

$rsync -a ${PGDATA}/ postgres@192.168.0.21:/home/postgres/main --exclude postmaster.pid

$psql -c "SELECT pg_stop_backup();"

192.168.0.21的/home/postgres/main目录下的内容为

4. Standby节点

PGDATA=/home/postgres/main

Standby节点的PGDATA路径就是Primary节点的PGDATA的副本

1）配置postgresql.conf

设置hot_standby为

hot_standby= on

2）编辑recovery.conf，文件路径为$(PGDATA)/recovery.conf，内容为

---------------------------------------------------------------------------------------------------------------------------

# Specifies whether to start the server as a standby. In streaming replication,

# this parameter must to be set to on.
standby_mode = 'on'

# Specifies a connection string which is used for the standby server to connect
# with the primary.
primary_conninfo = 'host=192.168.0.11 port=5432 user=postgres'
# Specifies a trigger file whose presence should cause streaming replication to
# end (i.e., failover).
trigger_file = '/home/postgres/trigger'

# Specifies a command to load archive segments from the WAL archive. If
# wal_keep_segments is a high enough number to retain the WAL segments
# required for the standby server, this may not be necessary. But
# a large workload can cause segments to be recycled before the standby
# is fully synchronized, requiring you to start again from a new base backup.
restore_command = 'cp /home/postgres/archive/%f %p'

--------------------------------------------------------------------------------



3）复制pg_xlog下的所有文件到/home/postgres/archive目录下
   

4）启动Standby节点，完成Replication。
   

完成Streaming Replication配置。

5. 验证

使用psql连接primary，创建test数据库。刷新从节点，可以看到在其上也生成了test数据库。

6. 问题

1）Standby的data目录是空的，其所有配置均是在rsync之后；

2）recovery.conf文件其实只需要修改standby_mode 和 primary_info，其余并不是必须的；

3）注意Primary的防火墙，必要时关闭，免得干扰集群配置；

4）如果从节点PostgreSQL已有数据，需要全部删除。

参考:

PostgreSQL配置Streaming Replication集群(http://www.cnblogs.com/marsprj/archive/2013/03/04/2943373.html)

http://opensourcedbms.com/dbms/setup-replication-with-postgres-9-2-on-centos-6redhat-el6fedora/