环境：

• OS:
  

  [ha@node0 ~]$ uname -a
  Linux node0 2.6.32-358.el6.x86_64 #1 SMP Fri Feb 22 00:31:26 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
  

• 内存：1G
• CPU：1核
• 数据库:
  

  postgres=# select version();
                                                      version                     
  --------------------------------------------------------------------------------------------------------
   PostgreSQL 9.4.5 on x86_64-unknown-linux-gnu, compiled by gcc (GCC) 4.4.7 20120
  313 (Red Hat 4.4.7-16), 64-bit
  (1 row)
   
  postgres=#
  

• .bash_profile
  

  [ha@node0 ~]$ cat .bash_profile 
  # .bash_profile
   
  # Get the aliases and functions
  if [ -f ~/.bashrc ]; then
      . ~/.bashrc
  fi
   
  # User specific environment and startup programs
   
  export PGHOME=/home/ha/pgdb/
  export PGDATA=/home/ha/pgdb/data/
  export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$PGHOME/lib/
  export PATH=$PGHOME/bin:$PATH:$HOME/bin
  

搭建过程：

1、主库配置

1. postgresql.conf：
   

   listen_addresses = '*'
   wal_level = hot_standby
   archive_mode = off
   max_wal_senders = 3
   wal_keep_segments = 16

   这里要说明的是参数archive_mode，我在实验过程中有一次发现参数archive_mode和archive_command在不设置的情况下也可以完成流复制，所以我对此进行了调研，发现francs已经对此进行了解释，这里引用francs的结论：
   

   在搭建流复制环境时，并不必须设置 archive_mode 参数为 on ，很多资料在介绍搭建流复制环境时设置这个参数为 on ，可能是出于开启 WAL 归档更安全的原因，因为在主库宕机并且较长时间不能恢复时，从库依然可以读取归档目录的 WAL，从而保证不丢数据; 另一方面，如果主库设置了较大的 wal_keep_segments ，也可以不用开启archive_mode，因为主库保留了足够的 WAL，从而大大降低了因从库所需要的 WAL 被主库覆盖而需要从归档去取 WAL 的情况。所以从这方面说，archive_mode 参数的设置与搭建流复制并没有直接关系。 提示： 对于比较繁忙的库，在搭建流复制从库时，建议主库设置较大的 wal_keep_segments 参数。

2. pg_hba.conf
   

   host    all             all             192.168.238.0/24        md5
   host    replication     rep             192.168.238.0/24        trust
   

   这里说明的是，网上有其他对replication设置为md5，并建立.pgpass文件，这种方法也是可行的。

3. 新建用户rep
   

   create user rep replication encrypted password 'rep';
   

2.使用pg_basebackup进行从库备份

[ha@localhost pgdb]$ pg_basebackup -D $PGDATA -F p -X stream -v -P -h 192.168.238.130 -U rep
transaction log start point: 0/2000028 on timeline 1
pg_basebackup: starting background WAL receiver
20945/20945 kB (100%), 1/1 tablespace                                         
transaction log end point: 0/20000F0
pg_basebackup: waiting for background process to finish streaming ...
pg_basebackup: base backup completed
[ha@localhost pgdb]$ ll
total 20
drwxrwxr-x.  2 ha ha 4096 Dec 26 00:54 bin
drwx------. 18 ha ha 4096 Dec 26 12:02 data
drwxrwxr-x.  4 ha ha 4096 Dec 26 00:54 include
drwxrwxr-x.  4 ha ha 4096 Dec 26 00:54 lib
drwxrwxr-x.  4 ha ha 4096 Dec 26 00:54 share
[ha@localhost pgdb]$ cd data/
[ha@localhost data]$ ls
backup_label  pg_hba.conf    pg_replslot   pg_subtrans  postgresql.auto.conf
base          pg_ident.conf  pg_serial     pg_tblspc    postgresql.conf
global        pg_logical     pg_snapshots  pg_twophase
pg_clog       pg_multixact   pg_stat       PG_VERSION
pg_dynshmem   pg_notify      pg_stat_tmp   pg_xlog

这里需要对目录进行一下说明：data目录可以通过pg_basebackup自动创建，但是其他表空间，需要手动创建并赋权，这里需要注意的是，权限为700。

3.从库配置

1. postgresql.conf
   

   hot_standby = on
   

2. recovery.conf
   

   standby_mode = on
   primary_conninfo = 'host=192.168.238.130 port=5432 user=rep'
   trigger_file = '/home/ha/pgdb/pg.trigger.file'
   

4.备库启动前，主库进程

[ha@localhost pgdb]$ ps -ef | grep post
root       2124      1  0 04:47 ?        00:00:00 /usr/libexec/postfix/master
postfix    2147   2124  0 04:47 ?        00:00:00 qmgr -l -t fifo -u
postfix   10385   2124  0 11:27 ?        00:00:00 pickup -l -t fifo -u
ha        10691      1  0 12:33 pts/3    00:00:00 /home/ha/pgdb/bin/postgres_ora
ha        10693  10691  0 12:33 ?        00:00:00 postgres: checkpointer process   
ha        10694  10691  0 12:33 ?        00:00:00 postgres: writer process      
ha        10695  10691  0 12:33 ?        00:00:00 postgres: wal writer process   
ha        10696  10691  0 12:33 ?        00:00:00 postgres: autovacuum launcher process   
ha        10697  10691  0 12:33 ?        00:00:00 postgres: stats collector process   
ha        10717   4087  0 12:37 pts/3    00:00:00 grep post

5.备库启动后

1. 主库进程
   

   [ha@localhost pgdb]$ ps -ef | grep post
   root       2124      1  0 04:47 ?        00:00:00 /usr/libexec/postfix/master
   postfix    2147   2124  0 04:47 ?        00:00:00 qmgr -l -t fifo -u
   postfix   10385   2124  0 11:27 ?        00:00:00 pickup -l -t fifo -u
   ha        10691      1  0 12:33 pts/3    00:00:00 /home/ha/pgdb/bin/postgres_ora
   ha        10693  10691  0 12:33 ?        00:00:00 postgres: checkpointer process   
   ha        10694  10691  0 12:33 ?        00:00:00 postgres: writer process      
   ha        10695  10691  0 12:33 ?        00:00:00 postgres: wal writer process   
   ha        10696  10691  0 12:33 ?        00:00:00 postgres: autovacuum launcher process   
   ha        10697  10691  0 12:33 ?        00:00:00 postgres: stats collector process   
   ha        10718  10691  0 12:37 ?        00:00:00 postgres: wal sender process rep 192.168.238.131(59195) streaming 0/3000060
   ha        10720   4087  0 12:37 pts/3    00:00:00 grep post
   

2. 备库进程
   

   [ha@localhost data]$ ps -ef | grep post
   root       2086      1  0 04:48 ?        00:00:00 /usr/libexec/postfix/master
   postfix    2108   2086  0 04:48 ?        00:00:00 qmgr -l -t fifo -u
   postfix    9657   2086  0 11:27 ?        00:00:00 pickup -l -t fifo -u
   ha         9782      1  0 12:36 pts/2    00:00:00 /home/ha/pgdb/bin/postgres
   ha         9783   9782  0 12:36 ?        00:00:00 postgres: startup process   recovering 000000010000000000000003
   ha         9784   9782  0 12:36 ?        00:00:00 postgres: checkpointer process   
   ha         9785   9782  0 12:36 ?        00:00:00 postgres: writer process   
   ha         9786   9782  0 12:36 ?        00:00:00 postgres: stats collector process   
   ha         9787   9782  0 12:36 ?        00:00:00 postgres: wal receiver process   streaming 0/3000060
   ha         9792   3744  0 12:37 pts/2    00:00:00 grep post
   

6.实验效果

1. 主库
   

   [ha@localhost pgdb]$ psql postgres
   psql (9.4.5)
   Type "help" for help.
    
   postgres=# create table test(id int);
   CREATE TABLE
   postgres=# insert into test values (1),(2);
   INSERT 0 2
   postgres=# select * from test ;
    id 
   ----
     1
     2
   (2 rows)
    
   postgres=#
   

2. 备库
   

   [ha@localhost data]$ psql postgres
   psql (9.4.5)
   Type "help" for help.
    
   postgres=# select * from test ;
    id 
   ----
     1
     2
   (2 rows)