PostgreSQL配置Streaming Replication集群

運行環境：

Primary:      192.168.111.150

Standby:     192.168.111.151

                  192.168.111.152

OS：           CentOS5.8                   

PostgreSQL: 9.1.2 版本以上才支持Streaming Replication。

 

1. 環境規划

   Primary和Standby節點最好有相同的環境。

 

2. 安裝PostgreSQL

1）在Primary和Standy節點上安裝PostgreSQL軟件，安裝路徑為/opt/pgsql-9.1.2

2）設置postgres用戶的環境變量

     PGHOME=/opt/pgsql-9.1.2

     PGDATA=/storage0/database/postgres/main

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

 

3. Primary節點

1）切換到postgres用戶

     $su - postgres

2）初始化數據庫

     $initdb

3）配置pg_hba.conf

     在# IPv4 local connections下面添加一行，設置PostgreSQL的訪問及其權限

     host    all             all             192.168.111.1/24        trust

     在# replication privilege.下面添加一行，設置replication用戶及權限

     host     replication     postgres        192.168.111.1/24 trust

4）配置postgresql.conf

     配置監聽，修改listen_addresses = 'localhost'

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

     配置Primary Replication參數

     wal_level = hot_standby

     max_wal_senders = 5

     wal_keep_segments = 32

     archive_mode = on

     archive_command = 'cp %p /storage0/database/postgres/archive/%f < /dev/null'

     "/storage0/database/postgres/archive"是Replication的archive的存儲路徑。PostgreSQL會將Replication的WAL保存在 "/storage0/database/postgres/archive"路徑下。

5) 啟動Primary上的PostgreSQL數據庫

    $pg_ctl start

6) 在primary上執行以下命令

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

    將Primary的PGDATA目錄下的文件，除了postmaster.pid復制到Standby節點的“/storage0/database/postgres/main”目錄下，該目錄是 Standby節點上的PostgreSQL數據庫的PGDATA目錄。

    $rsync -a ${PGDATA}/ postgres@192.168.111.151:/storage0/database/postgres/main --exclude postmaster.pid

    $psql -c "SELECT pg_stop_backup()"

    

    192.168.111.151的/storage0/database/postgres/main目錄下的內容為

    

4. Standby節點

    PGDATA=/storage0/database/postgres/main

    Standby節點的PGDATA路徑就是Primary節點的PGDATA的副本

1）配置postgresql.conf

     設置hot_standby為

     hot_standby= on

2）編輯recovery.conf，文件路徑為$(PGDATA)/recovery.conf，內容為

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

# 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=192.168.111.150 port=5432 user=postgres'
# Specifies a trigger file whose presence should cause streaming replication to
# end (i.e., failover).
trigger_file = '/storage0/database/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 /storage0/database/postgres/archive/%f %p'

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3）復制pg_xlog下的所有文件到/storage0/database/postgres/archive目錄下


4）啟動Standby節點，完成Replication。


完成Streaming Replication配置。

啟動pgAdmin，連接192.168.111.150節點，創建test數據庫，刷新 192.168.111.151節點。可以看到在192.168.111.151上也生成了test數據庫。