Add RPM
yum install https://download.postgresql.org/pub/repos/yum/9.5/redhat/rhel-7-x86_64/pgdg-centos95-9.5-3.noarch.rpm
Install PostgreSQL 9.5
yum install postgresql95-server postgresql95-contrib
Initialize the database
/usr/pgsql-9.5/bin/postgresql95-setup initdb
boot
systemctl enable postgresql-9.5.service
Start the database service
systemctl start postgresql-9.5.service
Query version
psql --version
Change password
su - postgres psql -U postgres ALTER USER postgres WITH PASSWORD '123456' \q
postgresql9.5 master-slave replication
| system version |
CPU name |
IP addresses |
postgresql version |
Character |
| centos7.6 |
postgresql-master |
192.168.216.130 |
9.5.18 |
Main library |
| centos7.6 |
postgresql-slave |
192.168.216.129 |
9.5.18 |
From the library |
Description: The two servers are already pre-installed with yum good way postgresql 9.5, note that there is no need to initialize and start the service from the library , this document is a master-slave replication configuration, the main library can read and write, read only from the library You can not write data.
Main library configuration:
>> CAT / var / lib / pgSQL / 9.5 / Data / << the postgresql.conf the EOF wal_level hot_standby = # (default is minimal) max_wal_senders = 2 # (default 0) wal_keep_segments # = 64 (default 0) the EOF
Explanation
wal_level represents start to build Hot Standby, max_wal_senders will need to be set to a number greater than 0, which represents the main library how many concurrent standby database up to, and the last wal_keep_segments should also be set to a largest possible value, in order to prevent the main library WAL logs generated too fast, the log has not had time to transmit standby to be covered, but need to consider disk space permits, the size of a WAL log file is 16M
As shown above, a WAL log file is 16M, if wal_keep_segments set to 64, that will standby database keeps 64 WAL log files, it will take up disk space 16 * 64 = 1GB, it is necessary to consider, in the disk the case is set larger space allows, it will reduce the risk of re-build of standby. Next you need to create a super user in the main library dedicated to make standby connection to mop WAL log
Create a synchronization user
postgres=# create user rep1 superuser password '123456';
Modify the configuration file, to allow connecting the main bank from the bank server log data to mop WAL
vim /var/lib/pgsql/9.5/data/pg_hba.conf host replication rep1 192.168.216.0/24 md5
Here you need to configure the listener address as the default monitor local
vi /var/lib/pgsql/9.5/data/postgresql.conf listen_addresses = '192.168.216.130'
Restart Service
systemctl restart postgresql-9.5.service
From the library configuration:
Execute the following command to back up data from the primary database
/usr/pgsql-9.5/bin/pg_basebackup -h 192.168.216.130 -U rep1 -F p -x -P -R -D /var/lib/pgsql/9.5/data/ -l rep_backup
The backup process is actually a process of copying data from the master data directory in the physical library.
Parameter Description
-F specifies the format of the output, support p (as output) or t (tar output format).
-x represents the job was started, another stream copy start WAL coupled to receive logs from the primary library.
-p representation allows real-time during the backup in progress print backup.
-R represent recovery.conf file will be automatically generated at the end of the backup, thus avoiding the manual creation.
-D specify which directory the backup is written, attention: the need to manually clear the data from the catalog backup before making basis.
-l represents specify the identity of a backup.
Since the copied file owner is root here need to change the owner and group
chown -R postgres.postgres /var/lib/pgsql/9.5/data/
Modify the configuration file from the library
vim /var/lib/pgsql/9.5/data/postgresql.conf
247 #hot_standby = off # "on" allows queries during recovery
248 hot_standby = on #添加此行
Note that row 59 need to annotate the monitoring address, since all copies of data files in the master database /, so there needs to be modified
Start from the library
systemctl start postgresql-9.5.service
test:
Written test from the library:
Create a test table in the main library, while the query from the library
In the query from the library: as shown below
