pg_rman用法
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参考技术A 简介pg_rman的用法
pg_rman使用前提
pg_rman是一款专门为postgresql设计的在线备份恢复的工具。其支持在线（热备份）和基于时间点备份方式。
postgresql10以上版本都是自带pg_rman工具的，如果没有请单独安装。
此处无需记忆，对文章后面使用的参数不理解时，再回来看。
1、创建备份目录
2、设置环境变量
3、修改postgresql.conf配置文件
3、pg_rman init 初始化
1、备份
2、校验备份集
重点注意：pg_rman 的备份必须都是经过验证过的，否则不能进行恢复和增量备份。
3、pg_rman 列出备份集
查看生成的备份文件所在目录
重点注意：
增量备份是基于文件系统的update time时间线.
增量备份前提：
- 必须要有个对应的全库备份。
- 当全库备份后需要验证备份集。
1、验证备份集
如上，我们已得到一个全库备份。因此只需要从验证备份开始。
2、备份
3、再次校验备份集
4、pg_rman 列出备份集
删除备份有两种方式
1、直接在fullback文件夹里面删除对应时间点的备份
2、使用 pg_rman delete -f "时间点" 删除。再删除增量备份的同时，自动会将全量备份也删除掉。如下
重点注意：恢复时需要先停库。
原地覆盖式恢复
pg_rman restore -B /postgresql-backup/backups/ --recovery-target-time "2020-04-16 13:18:32" --hard-copy
--如果不指定recovery-target-time，则恢复到最新时间
--如果不指定hard-copy，则归档日志目录里的归档日志是使用的硬连接指向备份目录中的归档日志，加了这个参数的话，则是直接把备份目录中的归档日志拷贝到归档日志目录
1、创建新的data目录，并修改权限
2、修改postgres用户的环境变量
3、恢复
pg_rman备份恢复测试
环境描述
1.OS
CentOS Linux release 7.2.1511 (Core) X64
2.PostgreSQL
PostgreSQL 9.6.1
3.pg_rman
pg_rman-1.3.3-pg96.tar.gz v1.3.3
注意：请下载版本对应的源码包。
https://github.com/ossc-db/pg_rman/releases/download/v1.3.3/pg_rman-1.3.3-pg96.tar.gz
pg_rman-1.3.3.tar.gz（此源码编译过程中报错）
系统包
zlib-devel
二、pg_rman安装
1.安装pg_rman
root用户登录
export PATH=/opt/pgsql/9.6.1/bin:$PATH
export LD_LIBRARY_PATH=/opt/pgsql/9.6.1/lib
export MANPATH=/opt/pgsql/9.6.1/share/man:$MANPATH
# tar zxvf pg_rman-9_6_STABLE.tar.gz
# cd pg_rman-9_6_STABLE/
# make
......
......
gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -O2 backup.o catalog.o data.o delete.o dir.o init.o parray.o pg_rman.o restore.o show.o util.o validate.o xlog.o pgsql_src/pg_ctl.o pgut/pgut.o pgut/pgut-port.o -L/opt/pgsql/9.6.1/lib -lpgcommon -lpgport -L/opt/pgsql/9.6.1/lib -lpq -L/opt/pgsql/9.6.1/lib -Wl,--as-needed -Wl,-rpath,‘/opt/pgsql/9.6.1/lib‘,--enable-new-dtags -lpgcommon -lpgport -lz -lreadline -lrt -lcrypt -ldl -lm -o pg_rman
# make install
/usr/bin/mkdir -p ‘/opt/pgsql/9.6.1/bin‘
/usr/bin/install -c pg_rman ‘/opt/pgsql/9.6.1/bin‘
#
2.安装验证
su - postgres
$ pg_rman --version
pg_rman 1.3.3
3.配置数据库参数
wal_level = replica
archive_mode = on
archive_command = ‘test ! -f /pg_arclog/%f && cp %p /pg_arclog/%f‘
--- root user
mkdir /backup_pg_rman /pg_arclog
chown -R postgres:postgres /backup_pg_rman
chown -R postgres:postgres /pg_arclog
--- postgresql
# pg_rman init -B $backup_dir
三、备份恢复测试
1.备份数据(full<0> + incremental<1>)
# full
export PGDATA=/pgdata96
export BACKUP_PATH=/backup_pg_rman
$ echo $PGDATA
/pgdata96
$ echo $BACKUP_PATH
/backup_pg_rman
$
--- init backup dir: pg_rman init -B $backup_dir -D $PGDATA(当不配置环境变量时，手工指定，注意路径末尾不添加‘/‘结束符)
$ pg_rman init
INFO: ARCLOG_PATH is set to ‘/pg_arclog‘
INFO: SRVLOG_PATH is set to ‘/pgdata96/pg_log‘
$
$ cat $BACKUP_PATH/pg_rman.ini
ARCLOG_PATH=‘/pg_arclog‘
SRVLOG_PATH=‘/pgdata96/pg_log‘
--- full backup
$ pg_rman backup --backup-mode=full --with-serverlog --progress
INFO: copying database files
Processed 1172 of 1172 files, skipped 0
INFO: copying archived WAL files
Processed 3 of 3 files, skipped 0
INFO: copying server log files
Processed 4 of 4 files, skipped 0
INFO: backup complete
INFO: Please execute ‘pg_rman validate‘ to verify the files are correctly copied.
--- validate backup
$ pg_rman validate, status: done
INFO: validate: "2017-03-06 16:43:39" backup, archive log files and server log files by CRC
INFO: backup "2017-03-06 16:43:39" is valid
--- show backup, status: ok
$ pg_rman show
==========================================================
StartTime Mode Duration Size TLI Status
==========================================================
2017-03-06 16:43:39 FULL 0m 58MB 1 OK
$
--- incremental
$ pg_rman backup --backup-mode=incremental --with-serverlog --progress
INFO: copying database files
Processed 1172 of 1172 files, skipped 1115
INFO: copying archived WAL files
Processed 48 of 48 files, skipped 3
INFO: copying server log files
Processed 4 of 4 files, skipped 3
INFO: backup complete
INFO: Please execute ‘pg_rman validate‘ to verify the files are correctly copied.
$
--- validate backup
$ pg_rman validate
INFO: validate: "2017-03-06 17:04:45" backup, archive log files and server log files by CRC
INFO: backup "2017-03-06 17:04:45" is valid
$
--- show, status: ok
$ pg_rman show detail
============================================================================================================
StartTime Mode Duration Data ArcLog SrvLog Total Compressed CurTLI ParentTLI Status
============================================================================================================
2017-03-06 17:04:45 INCR 0m 401MB 738MB 27kB 1136MB false 1 0 OK
2017-03-06 16:43:39 FULL 0m 30MB 33MB 206kB 58MB false 1 0 OK
$
2.模拟灾难恢复
1).删除PGDATA 目录下所有文件
安全停止数据库,删除文件
$ pg_ctl stop -m immediate -D /pgdata96/
$ cd /pgdata96
$ rm -rf *.*
2).恢复备份
--- postgres user
$ export PGDATA=/pgdata96
$ export BACKUP_PATH=/backup_pg_rman
$ pg_rman restore
WARNING: pg_controldata file "/pgdata96/global/pg_control" does not exist
WARNING: pg_controldata file "/pgdata96/global/pg_control" does not exist
INFO: the recovery target timeline ID is not given
INFO: use timeline ID of latest full backup as recovery target: 1
INFO: calculating timeline branches to be used to recovery target point
INFO: searching latest full backup which can be used as restore start point
INFO: found the full backup can be used as base in recovery: "2017-03-06 16:43:39"
INFO: copying online WAL files and server log files
INFO: clearing restore destination
INFO: validate: "2017-03-06 16:43:39" backup, archive log files and server log files by SIZE
INFO: backup "2017-03-06 16:43:39" is valid
INFO: restoring database files from the full mode backup "2017-03-06 16:43:39"
INFO: searching incremental backup to be restored
INFO: validate: "2017-03-06 17:04:45" backup, archive log files and server log files by SIZE
INFO: backup "2017-03-06 17:04:45" is valid
INFO: restoring database files from the incremental mode backup "2017-03-06 17:04:45"
INFO: searching backup which contained archived WAL files to be restored
INFO: backup "2017-03-06 17:04:45" is valid
INFO: restoring WAL files from backup "2017-03-06 17:04:45"
INFO: restoring online WAL files and server log files
INFO: generating recovery.conf
INFO: restore complete
HINT: Recovery will start automatically when the PostgreSQL server is started.
$
3).启动数据库验证数据
# /etc/init.d/postgresql start
Starting PostgreSQL: ok
#
切换至postgres用户,然后验证数据
异常停止数据恢复
描述：当数据库没有成功执行检查点完成,恢复时可能会丢失数据,错误排查
现象：启动数据库失败时
$ more postgresql-Mon.log
2017-03-06 17:20:47 CST [3240]: [1-1] user=,db= LOG: database system was interrupted; last known up at 2017-03-06 17:04:51 CST
2017-03-06 17:20:47 CST [3240]: [2-1] user=,db= LOG: starting archive recovery
2017-03-06 17:20:47 CST [3240]: [3-1] user=,db= LOG: invalid primary checkpoint record
2017-03-06 17:20:47 CST [3240]: [4-1] user=,db= LOG: invalid secondary checkpoint record
2017-03-06 17:20:47 CST [3240]: [5-1] user=,db= PANIC: could not locate a valid checkpoint record
2017-03-06 17:20:47 CST [3238]: [3-1] user=,db= LOG: startup process (PID 3240) was terminated by signal 6: Aborted
2017-03-06 17:20:47 CST [3238]: [4-1] user=,db= LOG: aborting startup due to startup process failure
2017-03-06 17:20:47 CST [3238]: [5-1] user=,db= LOG: database system is shut down
2017-03-06 17:21:23 CST [3269]: [1-1] user=,db= LOG: database system was interrupted; last known up at 2017-03-06 17:04:51 CST
2017-03-06 17:21:23 CST [3269]: [2-1] user=,db= LOG: starting archive recovery
2017-03-06 17:21:23 CST [3269]: [3-1] user=,db= LOG: invalid primary checkpoint record
2017-03-06 17:21:23 CST [3269]: [4-1] user=,db= LOG: invalid secondary checkpoint record
2017-03-06 17:21:23 CST [3269]: [5-1] user=,db= PANIC: could not locate a valid checkpoint record
2017-03-06 17:21:23 CST [3267]: [3-1] user=,db= LOG: startup process (PID 3269) was terminated by signal 6: Aborted
2017-03-06 17:21:23 CST [3267]: [4-1] user=,db= LOG: aborting startup due to startup process failure
2017-03-06 17:21:23 CST [3267]: [5-1] user=,db= LOG: database system is shut down
$
处理步骤说明：
重置事务日志
仅保留备份时数据
$ pg_resetxlog -f /pgdata96
Transaction log reset
$
然后启动数据库,验证部分数据
本文出自 “yiyi” 博客，请务必保留此出处http://heyiyi.blog.51cto.com/205455/1903709
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