postgresql搭建从库
master 10.40.196.27
slave 10.40.55.69
需求：master和slave作为主从流复制，当master宕机后，slave切换为新主继续服务；然而当master恢复故障后，作为从重新加入主从流复制。
master
1.创建复制用户
create user rep replication password 'rep';
2.设置pg_hba.conf
-bash-4.1$ cat pg_hba.conf|grep repli|grep -v '#'
host replication rep 10.40.55.69/32 md5
3.设置主库postgresql.conf
#add by b
wal_level='hot_standby'
archive_mode = on
archive_command = 'ssh 10.40.55.201 test ! -f /backup2/pgdata/digoal/19627/data04/pg93archdir/%f && scp %p
10.40.55.201:/backup2/pgdata/digoal/19627/data04/pg93archdir/%f'
#archive_command = 'archive.sh %p %f'
max_worker_processes = 16
max_wal_senders = 8
wal_keep_segments = 32
4.重启数据库
pg_ctl restart -D /data/pgsql/data
slave配置
1.创建数据目录
[postgres@db-hx-55-69 ~]$ echo $PGDATA
/opt/niu/postgresql/data
mkdir -p /opt/niu/postgresql/data;cd /opt/niu/postgresql
chown -R postgres.postgres data
chmod 700 data
cd $PGDATA (/opt/niu/postgresql/data)
rm -rf *
master 196.27
-bash-4.1$ cd $PGDATA/pg_tblspc/
-bash-4.1$ ll
total 0
lrwxrwxrwx 1 postgres postgres 25 Jan 12 13:34 1031792 -> /opt/pgsql/bi_erp_itf_tbs
lrwxrwxrwx 1 postgres postgres 14 May 20 2016 16385 -> /opt/pgsql/tbs
[root@db-hx-55-69 pgsql]# pwd
/opt/pgsql
[root@db-hx-55-69 pgsql]# rm -rf *
2.使用pg_basebackup生成基础备份，放到slave上数据目录下
[postgres@db-hx-55-69 ~]$ pg_basebackup -D /opt/niu/postgresql/data -Fp -Xs -v -P -h 10.40.196.27 -p 5432 -U rep
Password: rep
3.配置recovery.conf
vi $PGDATA/recovery.conf
standby_mode = on
trigger_file = '/opt/niu/postgresql/pg.trigger'
primary_conninfo = 'host=10.40.196.27 port=5432 user=rep password=rep'
4.启动pgsql
$ pg_ctl start -D /opt/niu/postgresql/data
测试流复制
1.查看主库
主库$ ps -ef |grep postgres|grep sender |grep -v grep
postgres 89707 65237 0 00:15 ? 00:00:00 postgres: wal sender process rep 10.40.55.69(26717) streaming 9F1/51EE4FB0
确认主库中进程有“postgres: wal sender process”
2.查看从库
$ ps -ef |grep postgres |grep -v grep |grep receiver
postgres 14055 14013 1 00:15 ? 00:00:02 postgres: wal receiver process streaming 9F1/5423E000
确定备库进程中有”postgres: wal receiver process”
4.查看主备同步状态
postgres=# select * from pg_stat_replication;
pid |
usesysid | usename | application_name | client_addr | client_hostname |
client_port | backend_start | backend_xmin |
usesysid | usename | application_name | client_addr | client_hostname |
client_port | backend_start | backend_xmin |
state | sent_location
| write_location | flush_location | replay_location | sync_priority | sync_state
-------+----------+---------+------------------+-------------+-----------------+-------------+-------------------------------+--------------
+-----------+---------------
+----------------+----------------+-----------------+---------------+------------
89707
| 988512 | rep | walreceiver | 10.40.55.69
| | 26717 | 2018-03-10 00:15:14.610005+08
| |
| 988512 | rep | walreceiver | 10.40.55.69
| | 26717 | 2018-03-10 00:15:14.610005+08
| |
streaming | 9F1/6073C458
| 9F1/6073C458 | 9F1/6073C458 | 9F1/6073BFE0 | 0 | async
(1 row)
字段state显示的同步状态有：startup（连接中）、catchup（同步中）、streaming（同步）；
字段sync_state显示的模式有：async（异步）、sync（同步）、potential（虽然现在是异步模式，但是有可能升级到同步模式）
[postgres@db-hx-55-69 pgsql]$ psql
psql: FATAL: the database system is starting up