Stream Replication

master防火牆配置

master :10.10.56.16 
slave  :10.10.56.17
slave  :10.10.56.18
slave  :10.10.56.19 

在 master 上搭建PostgeSQL 環境基於配置(一)，具體請參考 搭建PostgreSQL 安裝環境(一)

安裝成功後,在master的客戶端認證檔案pg_hba.conf 後新增如下：

[email protected]:~> vim /pgdata/9.6/poc/data/pg_hba.conf 

# TYPE   DATABASE   USER         ADDRESS               METHOD
 

host    replication repl        10.10.56.17/32          md5
host    replication repl        10.10.56.18/32          md5
host    replication repl        10.10.56.19/32          md5

上述表示：允許地址為17、18、19的使用者repl 通過MD5密碼驗證 從主機進行復制。

修改配置檔案後，若PostgeSQL 服務在執行 則reload，沒有執行則 start 使之生效：

[email protected]-db1
 
:~> /opt/pgsql-9.6/bin/pg_ctl -D /pgdata/9.6/poc/data/ reload
server signaled
[email protected]-db1:~> 

master配置成功後，slave 安裝基本環境同 master ,區別在於 slave 從庫不需要進行 initdb 初始化資料庫

slave複製資料

[email protected]-db2:/pgdata/9.6/poc> /opt/pgsql-9.6/bin/pg_basebackup -h 10.10.56.16 -U repl -W -Fp -Pv -Xs -R -D
 
 /pgdata/9.6/poc/data/
Password: 
pg_basebackup: initiating base backup, waiting for checkpoint to complete
pg_basebackup: checkpoint completed
transaction log start point: 0/2000028 on timeline 1
pg_basebackup: starting background WAL receiver
29956/29956 kB (100%), 1/1 tablespace                                         
transaction log end point: 0/20000F8
pg_basebackup: waiting for background process to finish streaming ...
pg_basebackup: base backup completed

-h 表示主機地址          -W 表示需要密碼        -Fp 表示普通檔案格式輸出 
-Xs 表示通過流複製抓取備份日誌     -R 表示在輸出目錄預設建立一個recovery.conf檔案
-u 表示使用者     -D 指定資料庫存放的目錄

上述表示把資料從主庫master同步到slave 上

檢視slave的recovery配置檔案

[email protected]-db2:/pgdata/9.6/poc/data> cat recovery.conf
standby_mode = 'on'
primary_conninfo = 'user=repl password=123456 host=10.10.56.16 port=5432 sslmode=disable sslcompression=1'

啟動slave

[email protected]-db2:/home/postgres> /opt/pgsql-9.6/bin/pg_ctl -D /pgdata/9.6/poc/data/ start
server starting
[email protected]-db2:/home/postgres> FATAL:  data directory "/pgdata/9.6/poc/data" has group or world access
DETAIL:  Permissions should be u=rwx (0700).

解決方法：

postgres@clw-db2:/pgdata/9.6/poc> chmod 0700 data

啟動PG server

[email protected]-db2:/pgdata/9.6/poc> /opt/pgsql-9.6/bin/pg_ctl -D /pgdata/9.6/poc/data/ start
server starting
[email protected]-db2:/pgdata/9.6/poc> 

看到日誌輸出以下內容說明啟動成功：

[email protected]:/pgdata/9.6/poc> tail -f /pgdata/9.6/poc/data/pg_log/postgresql-2018-05-03_172139.csv
2018-05-03 17:21:39.838 CST,,,30454,,5aead4a2.76f6,2,,2018-05-03 17:21:38 CST,,0,LOG,00000,"database system is ready to accept read only connections",,,,,,,,,""

檢視主從是否已連線

[email protected]:~> /opt/pgsql-9.6/bin/psql -p 5432 -U postgres pocdb
psql (9.6.8)
Type "help" for help.

pocdb=# \x
Expanded display is on.
pocdb=#                                                 
pocdb=# select * from pg_stat_replication;
-[ RECORD 1 ]----+------------------------------
pid              | 21072
usesysid         | 16385
usename          | repl
application_name | walreceiver
client_addr      | 10.10.56.17
client_hostname  | 
client_port      | 43200
backend_start    | 2018-05-03 17:21:39.842751+08
backend_xmin     | 
state            | streaming
sent_location    | 0/3000220
write_location   | 0/3000220
flush_location   | 0/3000220
replay_location  | 0/3000220
sync_priority    | 0
sync_state       | async