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PostgreSQL数据库单机扩展为流复制
1. 在standby服务器安装postgres数据库,不需要初始化.
安装过程详见:http://www.cnblogs.com/ilifeilong/p/6979288.html
2. 在primary服务器创建具有REPLICATION权限的复制用户
postgres=# CREATE ROLE repl WITH REPLICATION PASSWORD ‘repl‘ LOGIN;
3. 允许复制用户远程连接到primary服务器
$ grep "^host" pg_hba.conf host all all 127.0.0.1/32 trust host replication repl 0.0.0.0/0 md5 host all all ::1/128 trust
4. 在primary服务器设置流复制相关的参数
$ mkdir /usr/local/pgsql/arch $ egrep "archive_mode|max_wal_senders|wal_keep_segments|archive_command|wal_level|hot_standby" postgresql.conf al_level = hot_standby # minimal, archive, hot_standby, or logical archive_mode = on # enables archiving; off, on, or always archive_command = ‘test ! -f /usr/local/pgsql/arch/%f && cp %p /usr/local/pgsql/arch/%f‘ max_wal_senders = 5 # max number of walsender processes wal_keep_segments = 30 # in logfile segments, 16MB each; 0 disables hot_standby = on # "on" allows queries during recovery #hot_standby_feedback = off # send info from standby to prevent
5. 重新启动primary服务器进程
$ pg_ctl stop -m fast
$ pg_ctl start
6. 对primary服务器做一个全备并传输到standby服务器
- 在primary服务器通过pg_(start|stop)_backup函数进行备份
postgres=# SELECT pg_start_backup(‘label‘, true); pg_start_backup ----------------- 7/E6000060 (1 row) $ rsync -az --progress ${PGDATA} postgres@10.189.100.195:/usr/local/pgsql/ --exclude postmaster.pid postgres=# SELECT pg_stop_backup(); NOTICE: pg_stop_backup complete, all required WAL segments have been archived pg_stop_backup ---------------- 7/E60005C8 (1 row)
- 在standby服务器通过pg_basebackup命令进行备份,要求standby的PGDATA目录为空
$ pg_basebackup --host=10.189.102.118 --username=repl --port=5432 --label=backup --verbose --progress --pgdata=http://www.mamicode.com/usr/local/pgsql/data --checkpoint=fast --format=p --xlog-method=stream Password: transaction log start point: 7/EA000028 on timeline 1 pg_basebackup: starting background WAL receiver 65933562/65933562 kB (100%), 1/1 tablespace transaction log end point: 7/EA000830 pg_basebackup: waiting for background process to finish streaming ... pg_basebackup: base backup completed
7. 设置standby数据库复制相关参数,使得standby失效转移后可以作为主库工作
$ mkdir /usr/local/pgsql/arch $ egrep "archive_mode|max_wal_senders|wal_keep_segments|archive_command|wal_level|hot_standby" postgresql.conf wal_level = hot_standby # minimal, archive, hot_standby, or logical archive_mode = on # enables archiving; off, on, or always archive_command = ‘test ! -f /usr/local/pgsql/arch/%f && cp %p /usr/local/pgsql/arch/%f‘ max_wal_senders = 5 # max number of walsender processes wal_keep_segments = 30 # in logfile segments, 16MB each; 0 disables hot_standby = on # "on" allows queries during recovery #hot_standby_feedback = off # send info from standby to prevent
8. 在standby文件创建恢复文件
$ cat recovery.conf restore_command = ‘cp /usr/local/pgsql/arch/%f "%p"‘ standby_mode = ‘on‘ primary_conninfo = ‘user=repl password=repl host=10.189.102.118 port=5432 sslmode=disable sslcompression=1‘ archive_cleanup_command = ‘pg_archivecleanup -d /usr/local/pgsql/arch %r >> /usr/local/pgsql/arch/archive_cleanup.log‘ trigger_file = ‘/usr/local/pgsql/data/trigger_active_standby‘
9. 启动standby数据库进程,自动启动流复制
$ pg_ctl start -w waiting for server to start....LOG: could not create IPv6 socket: Address family not supported by protocol LOG: redirecting log output to logging collector process HINT: Future log output will appear in directory "pg_log". done server started
10. 检查primary和standby数据库的延迟
- 通过函数和系统表查看
edbstore=# select * from pg_stat_replication; #在primary主库查看 -[ RECORD 1 ]----+------------------------------ pid | 15013 usesysid | 19206 usename | repl application_name | walreceiver client_addr | 10.189.100.195 client_hostname | client_port | 56072 backend_start | 2017-06-13 08:10:35.400508-07 backend_xmin | state | streaming sent_location | 7/EC01A588 write_location | 7/EC01A588 flush_location | 7/EC01A588 replay_location | 7/EC01A588 sync_priority | 0 sync_state | async edbstore=# SELECT pg_current_xlog_location(); #在primary主库查看 pg_current_xlog_location -------------------------- 7/EC01A588 (1 row) postgres=# select pg_last_xlog_receive_location(),pg_last_xlog_replay_location(),pg_last_xact_replay_timestamp(); #在standby备库查看 pg_last_xlog_receive_location | pg_last_xlog_replay_location | pg_last_xact_replay_timestamp -------------------------------+------------------------------+------------------------------- 7/EC01A588 | 7/EC01A588 | 2017-06-13 08:25:20.281568-07 (1 row)
- 通过进程查看
$ ps -ef | grep sender | grep -v grep #在primary库查看 postgres 15013 24883 0 08:10 ? 00:00:00 postgres: wal sender process repl 10.189.100.195(56072) streaming 7/EC01A668 $ ps -ef | grep receiver | grep -v grep #在standby库查看 postgres 12857 12843 0 08:10 ? 00:00:00 postgres: wal receiver process streaming 7/EC01A668
PostgreSQL数据库单机扩展为流复制
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