PostgreSQL备份之pg_basebackup

摘要: PostgreSQL备份之pg_basebackup

一、准备

连接上master节点创建replication用户

# CREATE ROLE replicator with login replication password 123456；

修改白名单pg_hba.conf

# host    replication    all        xxxxx/32    md5

二、制作基础备份

# pg_basebackup --format=tar \ #使用打包方式备份
--xlog-method=fetch \    #获取wal文件方式，等备份结束后把备份期间所有的wal备份
--compress=1 \    #压缩等级
--checkpoint=fast \    #执行检查点的方式
--label=backup \    #标签
--pgdata=/data/backup/ #备份目录
--progress \    #打印过程
--verbose \    #打印详细信息
--host='172.17.5.45' \    #master节点ip
--port=5432 \    #master节点端口
--user=postgres    #连接master节点的用户
Password:
transaction log start point: 2/34000028 on timeline 1
414272/414272 kB (100%), 3/3 tablespaces
transaction log end point: 2/34000128
pg_basebackup: base backup completed

备份默认会占用一个max_wal_senders连接，需要设置大一点，还可以使用

-r, --max-rate=RATE    maximum transfer rate to transfer data directory
(in kB/s, or use suffix "k" or "M")

限制传输速度

# ll backup/
total 123196
-rw-r--r--. 1 root root       129 Sep  8 01:21 25375.tar.gz
-rw-r--r--. 1 root root       128 Sep  8 01:21 25376.tar.gz
-rw-r--r--. 1 root root 126141406 Sep  8 01:22 base.tar.gz

base.tar.gz是数据目录的备份，其他两个是表空间的备份

三、恢复

1. 解压缩

# cd /data/backup/
# mkdir pgdata 25375 25376
# tar zxf base.tar.gz -C pgdata/
# ls pgdata/
backup_label  global   pg_dynshmem  pg_ident.conf  pg_logical    pg_notify    pg_serial     pg_stat      pg_subtrans  pg_twophase  pg_xlog               postgresql.conf
base          pg_clog  pg_hba.conf  pg_log         pg_multixact  pg_replslot  pg_snapshots  pg_stat_tmp  pg_tblspc    PG_VERSION   postgresql.auto.conf  recovery.conf
# tar zxf 25375.tar.gz -C 25375
# tar zxf 25376.tar.gz -C 25376
# ls
25375  25375.tar.gz  25376  25376.tar.gz  base.tar.gz  pgdata

2. 修改表空间软连接
<># ln -sf /data/backup/25375 pgdata/pg_tblspc/25375 [root@node2 backup]# ln -sf /data/backup/25376 pgdata/pg_tblspc/25376 [root@node2 backup]# ll pgdata/pg_tblspc/ total 0 lrwxrwxrwx. 1 root root 18 Sep 8 01:35 25375 -> /data/backup/25375 lrwxrwxrwx. 1 root root 18 Sep 8 01:35 25376 -> /data/backup/25376

3. 修改数据目录权限

# chown -R postgres:postgres pgdata/ 25375 25376
# chmod 0700 pgdata/
# ll
total 123208
drwxr-xr-x.  3 postgres postgres      4096 Sep  8 01:32 25375
-rw-r--r--.  1 root     root           129 Sep  8 01:21 25375.tar.gz
drwxr-xr-x.  3 postgres postgres      4096 Sep  8 01:33 25376
-rw-r--r--.  1 root     root           128 Sep  8 01:21 25376.tar.gz
-rw-r--r--.  1 root     root     126141406 Sep  8 01:22 base.tar.gz
drwx------. 19 postgres postgres      4096 Sep  8 01:31 pgdata

4. 启动

# su postgres
$ pg_ctl -D pgdata/ start
server starting
[    2015-09-08 05:40:04.510 UTC 11107 55ee74b4.2b63 1 0]LOG:  redirecting log output to logging collector process
[    2015-09-08 05:40:04.511 UTC 11107 55ee74b4.2b63 2 0]HINT:  Future log output will appear in directory "pg_log".
$ psql
psql (9.4.4)
Type "help" for help.

postgres=# \db+
List of tablespaces
Name    |  Owner   |      Location      | Access privileges | Options | Description
------------+----------+--------------------+-------------------+---------+-------------
pg_default | postgres |                    |                   |         |
pg_global  | postgres |                    |                   |         |
tblspc1    | postgres | /data/backup/25375 |                   |         |
tblspc2    | postgres | /data/backup/25376 |                   |         |
(4 rows)

四、 制作从库

1. 获取备份文件

# pg_basebackup --format=plain \    #使用目录方式
--write-recovery-conf \    #生成简单recovery.conf
--xlog-method=stream \    #使用stream的方式备份wal文件，会再占用一个max_wal_sender,wal文件一生成就会备份
--checkpoint=fast \
--label=backup \
--pgdata=/data/test_pgdata_94 \
--progress \
--verbose \
--host='172.17.5.45' \
--port=5432 \
--user=postgres
Password:
transaction log start point: 2/38000028 on timeline 1
pg_basebackup: starting background WAL receiver
397887/397887 kB (100%), 3/3 tablespaces
transaction log end point: 2/380000F0
pg_basebackup: waiting for background process to finish streaming ...
pg_basebackup: base backup completed

2. 修改目录权限

# chown -R postgres:postgres test_pgdata_94 tblspc1/ tblspc2/
# chmod 0700 test_pgdata_94
# ll test_pgdata_94
total 104
-rw-------. 1 postgres postgres  189 Sep  8 01:43 backup_label
drwx------. 6 postgres postgres 4096 Sep  8 01:43 base
drwx------. 2 postgres postgres 4096 Sep  8 01:43 global
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_clog
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_dynshmem
-rw-------. 1 postgres postgres 4581 Sep  8 01:43 pg_hba.conf
-rw-------. 1 postgres postgres 1636 Sep  8 01:43 pg_ident.conf
drwxr-xr-x. 2 postgres postgres 4096 Sep  8 01:43 pg_log
drwx------. 4 postgres postgres 4096 Sep  8 01:43 pg_logical
drwx------. 4 postgres postgres 4096 Sep  8 01:43 pg_multixact
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_notify
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_replslot
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_serial
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_snapshots
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_stat
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_stat_tmp
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_subtrans
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_tblspc
drwx------. 2 postgres postgres 4096 Sep  8 01:43 pg_twophase
-rw-------. 1 postgres postgres    4 Sep  8 01:43 PG_VERSION
drwx------. 3 postgres postgres 4096 Sep  8 01:43 pg_xlog
-rw-------. 1 postgres postgres   88 Sep  8 01:43 postgresql.auto.conf
-rw-------. 1 postgres postgres 4676 Sep  8 01:43 postgresql.conf
-rw-r--r--. 1 postgres postgres  131 Sep  8 01:43 recovery.conf
# ll tblspc1/
total 4
drwx------. 2 postgres postgres 4096 Sep  8 01:43 PG_9.4_201409291
# ll tblspc2
total 4
drwx------. 2 postgres postgres 4096 Sep  8 01:43 PG_9.4_201409291

3. 启动

# su postgres
$ pg_ctl -D test_pgdata_94 start
server starting
$ [    2015-09-08 05:49:55.383 UTC 12100 55ee7703.2f44 1 0]LOG:  redirecting log output to logging collector process
[    2015-09-08 05:49:55.383 UTC 12100 55ee7703.2f44 2 0]HINT:  Future log output will appear in directory "pg_log".

$ psql
psql (9.4.4)
Type "help" for help.

postgres=# \db+
List of tablespaces
Name    |  Owner   |   Location    | Access privileges | Options | Description
------------+----------+---------------+-------------------+---------+-------------
pg_default | postgres |               |                   |         |
pg_global  | postgres |               |                   |         |
tblspc1    | postgres | /data/tblspc1 |                   |         |
tblspc2    | postgres | /data/tblspc2 |                   |         |
(4 rows)

参考：http://www.postgresql.org/docs/9.4/static/app-pgbasebackup.html