postgresql-11主从复制（流复制）部署

主从机器分配
- IP地址 DB版本主从关系
  
  192.168.63.134 11.6 主
  
  192.168.63.141 11.6 从

安装postgresql

yum install https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm -y
yum install postgresql11 -y
yum install postgresql11-server -y

主库配置

主库初始化

/usr/pgsql-11/bin/postgresql-11-setup initdb
systemctl start postgresql-11

创建复制用户，进行主从同步使用

[root@localhost data]# sudo -i -u postgres
-bash-4.2$ psql
psql (11.6)
输入 "help" 来获取帮助信息.

postgres=# create role repl login replication encrypted password '123456';
CREATE ROLE

主库上配置从库采用repl账号

vim /var/lib/pgsql/11/data/pg_hba.conf

#只需要台添加下面两行，repl是用来做备份的用户，后面的192.168.63.0/24是该网段内的IP地址
host    replication     repl            192.168.63.0/24         md5
host    all             repl            192.168.63.0/24         trust

vim /var/lib/pgsql/11/data/postgresql.conf 

listen_addresses = '*'            # what IP address(es) to listen on;
port = 5432                # (change requires restart)
max_connections = 512            # (change requires restart)
shared_buffers = 128MB            # min 128kB
dynamic_shared_memory_type = posix    # the default is the first option
wal_level = hot_standby        # minimal, replica, or logical
archive_mode = on        # enables archiving; off, on, or always
archive_command = 'cp %p /var/lib/pgsql/11/data/pg_archive/%f'        # command to use to archive a logfile segment
max_wal_senders = 6        # max number of walsender processes
wal_keep_segments = 10240    # in logfile segments, 16MB each; 0 disables
wal_sender_timeout = 60s    # in milliseconds; 0 disables
log_directory = 'log'    # directory where log files are written

mkdir /var/lib/pgsql/11/data/pg_archive/
chown -R postgres.postgres /var/lib/pgsql/11/data

重启主库服务
```
systemctl restart postgresql-11
```

从库配置

从库安装完成后，不初始化，若已经初始化，删除其data目录

#把主节点所有的数据文件都会拷贝过来
[root@localhost ~]# pg_basebackup -h 192.168.63.134 -U repl -D /var/lib/pgsql/11/data/ -X stream -P
口令: 
25312/25312 kB (100%), 1/1 表空间
[root@localhost ~]# ls /var/lib/pgsql/12/data/
backup_label  current_logfiles  log         pg_commit_ts  pg_hba.conf    pg_logical    pg_notify    pg_serial     pg_stat      pg_subtrans  pg_twophase  pg_wal   postgresql.auto.conf
base          global            pg_archive  pg_dynshmem   pg_ident.conf  pg_multixact  pg_replslot  pg_snapshots  pg_stat_tmp  pg_tblspc    PG_VERSION   pg_xact  postgresql.conf

从库配置文件，根据下面的配置进行修改。

[root@localhost ~]# vim /var/lib/pgsql/11/data/postgresql.conf
listen_addresses = '*'            # what IP address(es) to listen on;
port = 5432                # (change requires restart)
max_connections = 1000            # (change requires restart)
shared_buffers = 128MB            # min 128kB
dynamic_shared_memory_type = posix    # the default is the first option
wal_level = replica        # minimal, replica, or logical
archive_mode = on        # enables archiving; off, on, or always
archive_command = 'cp %p /var/lib/pgsql/12/data/pg_archive/%f'        # command to use to archive a logfile segment
wal_sender_timeout = 60s    # in milliseconds; 0 disables
hot_standby = on            # "on" allows queries during recovery
max_standby_streaming_delay = 30s    # max delay before canceling queries
wal_receiver_status_interval = 10s    # send replies at least this often
hot_standby_feedback = on        # send info from standby to prevent
log_directory = 'log'    # directory where log files are written,

创建恢复文件recovery.conf。

[root@localhost 11]# cp /usr/pgsql-11/share/recovery.conf.sample /var/lib/pgsql/11/data/recovery.conf
[root@localhost 11]# vim /var/lib/pgsql/11/data/recovery.conf

# 调整参数：
recovery_target_timeline = 'latest'   #同步到最新数据
standby_mode = on          #指明从库身份
trigger_file = 'failover.now'
primary_conninfo = 'host=192.168.63.134 port=5432 user=repl password=123456'   #连接到主库信息

启动从库
```
systemctl start postgresql-11
```

验证主从配置

在主库上运行以下命令

postgres=# select client_addr,sync_state from pg_stat_replication;
  client_addr   | sync_state 
----------------+------------
 192.168.63.141 | async
(1 行记录)

可以创建一个数据库自行验证

IP地址	DB版本	主从关系
192.168.63.134	11.6	主
192.168.63.141	11.6	从

postgresql-11主从复制（流复制）部署

主从机器分配

安装postgresql

主库配置

主库初始化

从库配置