4.pg_rman介紹及使用

1.pg_rman 介紹

1.1 pg_rman 介紹

• pg_rman類似於oracle的rman備份策略，實現了全量、增量、歸檔的層級的備份，可以很靈活的管理PostgreSQL數據庫的備份，pg_rman是一款開源的pg的備份恢復插件支持在線和基於PITR的備份恢復方式。

• pg_rman特點：
    ○ 使用簡單.一個命令即可完成備份和恢復.
    ○ 支持在線全備,增量備份，歸檔備份.
    ○ 支持備份壓縮.通過gzip工具實現頁內壓縮.
    ○ 自動備份維護.自動刪除過期的WAL備份文件.
    ○ 支持備份驗證.
    ○ 恢復期間無事務丟失.支持基於PITR的配置文件生成器.


  • pg_rman 注意事項：
    ○  pg_rman 基於 pg_start_backup
    ○  pg_rman 基於 需要在本地安裝，不能遠程德份
    ○  pg_rman 需要下載對應的版本

1.2 pg_rman 下載

下載地址：
https://github.com/ossc-db/pg_rman/
PostgreSQL Rpm相關依賴、插件包下載地址：
https://yum.postgresql.org/10/redhat/rhel-6.7-x86_64/
手冊地址：
http://ossc-db.github.io/pg_rman/index.html

2.安裝使用

源碼包安裝方法：
  1、下載源碼包
         wget  <a href="https://github.com/ossc-db/pg_rman/releases/download/V1.3.7/pg_rman-1.3.7-pg10.tar.gz" style="text-decoration-skip-ink:none;">https://github.com/ossc-db/pg_rman/releases/download/V1.3.7/pg_rman-1.3.7-pg10.tar.gz</a>    
   2、解壓到指定目錄
         tar -zxvf  pg_rman-1.3.14-pg12.tar.gz -C /opt/
   3、進入到rman目錄進行編譯安裝
         cd /opt/pg_rman-1.3.14-pg12/
         make && make install

# 設置環境變量：
 PATH=$PATH:$HOME/bin
export PG_RMAN=/u01/postgresql/pg12
export PGHOME=/u01/postgresql/pg12
export PGDATA=/u01/postgresql/data
export PGLIB=/u01/postgresql/pg12/lib
export SRVLOG_PATH=/u01/postgresql/data/log
export ARCLOG_PATH=/u01/postgresql/archive
export BACKUP_PATH=/opt/pg_rman
export PATH=$PGHOME/bin:$PATH:$PG_RMAN/bin
export PATH

3.pg_rman 使用

3.1 pg_rman的用法

pg_rman的使用相對簡單核心8個命令
pg_rman manage backup/recovery of PostgreSQL database.
Usage:
  pg_rman OPTION init
  pg_rman OPTION backup
  pg_rman OPTION restore
  pg_rman OPTION show [DATE]
  pg_rman OPTION show detail [DATE]
  pg_rman OPTION validate [DATE]
  pg_rman OPTION delete DATE
  pg_rman OPTION purge

選項	功能
init	初始化備份目錄
backup	在線備份
restore	恢復
show	查看備份歷史
validate	驗證備份
delete	刪除備份文件
purge	從備份目錄中刪除已刪除備份

3.2 初始化備份目錄

首先需要初始化一個backup catalog，目錄將用於存放備份的文件，目錄也會存放一些元數據，例如備份的配置文件，數據庫的systemid，時間線文件歷史   
注意：在初始化的時候，要先確認環境變量是否設置正確。
root@mxl ~]# pg_rman init -B /opt/pg_rman
總用量 8
drwx------ 4 root root 35 11月 23 13:30 backup
-rw-r--r-- 1 root root 83 11月 23 13:30 pg_rman.ini
-rw-r--r-- 1 root root 40 11月 23 13:30 system_identifier
drwx------ 2 root root  6 11月 23 13:30 timeline_history

3.3 查看pg_rman的配置文件信息

[postgres@mxl pg_rman]$ cat pg_rman.ini 

ARCLOG_PATH=‘/home/postgres/arch’                        --歸檔目錄
SRVLOG_PATH=‘/home/postgres/data/log’                   --數據庫錯誤日志目錄
COMPRESS_DATA = YES                                   --壓縮數據
KEEP_ARCLOG_FILES = 10                                 --保存歸檔文件個數
KEEP_ARCLOG_DAYS = 10                                  --保存歸檔的天數
KEEP_DATA_GENERATIONS = 3                               --備份冗余度
KEEP_DATA_DAYS = 10                                   --保存備份集時間
KEEP_SRVLOG_FILES = 10                                 --保存日志文件個數
KEEP_SRVLOG_DAYS = 10                                  --保存日志文件天數

3.4 pg_rman的全量備份

如果沒有調設置export BACKUP_PATH=/opt/pg_rman  ，需要手動指明備份路徑 --backup-path=/opt/pg_rman
postgres@s2ahumysqlpg01-> pg_rman backup --backup-mode=full --with-serverlog  -h 127.0.0.1
INFO: copying database files
INFO: copying archived WAL files
INFO: copying server log files
INFO: backup complete
INFO: Please execute 'pg_rman validate' to verify the files are correctly copied.

一、pg_rman 校驗備份集：
postgres@s2ahumysqlpg01-> pg_rman show
=====================================================================
 StartTime           EndTime              Mode    Size   TLI  Status 
=====================================================================
2022-02-22 17:18:39  2022-02-22 17:19:12  FULL   942MB     5  DONE

二、未校驗備份集 Status 顯示為 DONE，開始校驗
[postgres@mxl pg_rman]$ pg_rman validate
INFO: validate: "2019-12-03 11:53:39" backup, archive log files and server log files by CRC
INFO: backup "2019-12-03 11:53:39" is valid
[postgres@mxl pg_rman]$ pg_rman show
=====================================================================
 StartTime           EndTime              Mode    Size   TLI  Status 
=====================================================================
2019-12-03 11:53:39  2018-12-03 11:54:00  FULL   461MB     1  OK

一、pg_rman 備份集查看：
[postgres@mxl pg_rman]$ pg_rman show
=====================================================================
 StartTime           EndTime              Mode    Size   TLI  Status 
=====================================================================
2019-12-03 11:53:39  2019-12-03 11:54:00  FULL   461MB     1  DONE

二、未校驗備份集 Status 顯示為 DONE，開始校驗
postgres@s2ahumysqlpg01-> pg_rman validate
INFO: validate: "2022-02-22 17:18:39" backup, archive log files and server log files by CRC
INFO: backup "2022-02-22 17:18:39" is valid


postgres@s2ahumysqlpg01->  pg_rman show
=====================================================================
 StartTime           EndTime              Mode    Size   TLI  Status 
=====================================================================
2022-02-22 17:18:39  2022-02-22 17:19:12  FULL   942MB     5  OK

3.5 pg_rman的增量備份

增量備份是基於文件系統的update time時間線，增量備份必須有個對應的全庫備份
postgres@s2ahumysqlpg01-> pg_rman backup --backup-mode=incremental --progress --compress-data  -h 127.0.0.1
INFO: copying database files
INFO: copying archived WAL filesipped 3028
Processed 16 of 16 files, skipped 13
INFO: backup complete
INFO: Please execute 'pg_rman validate' to verify the files are correctly copied.

備份集查看：
$ pg_rman show
    postgres@s2ahumysqlpg01-> pg_rman show
=====================================================================
 StartTime           EndTime              Mode    Size   TLI  Status 
=====================================================================
2022-02-22 17:22:54  2022-02-22 17:22:58  INCR    33kB     5  DONE
2022-02-22 17:18:39  2022-02-22 17:19:12  FULL   942MB     5  OK


postgres@s2ahumysqlpg01-> pg_rman validate
INFO: validate: "2022-02-22 17:22:54" backup and archive log files by CRC
INFO: backup "2022-02-22 17:22:54" is valid
postgres@s2ahumysqlpg01-> 
postgres@s2ahumysqlpg01-> 
postgres@s2ahumysqlpg01-> pg_rman show
=====================================================================
 StartTime           EndTime              Mode    Size   TLI  Status 
=====================================================================
2022-02-22 17:22:54  2022-02-22 17:22:58  INCR    33kB     5  OK
2022-02-22 17:18:39  2022-02-22 17:19:12  FULL   942MB     5  OK
postgres@s2ahumysqlpg01-> 

3.6 pg_rman 歸檔備份

一、pg_rman 歸檔備份：
歸檔備份就是靜態文件的拷貝。
$ pg_rman backup --backup-mode=archive --progress --compress-data 
$ pg_rman validate
$ pg_rman show

二、刪除備份集
刪除備份集指定日期之前的，不需要用來指定時間點之前的備份刪除掉
[postgres@mxl ~]$ pg_rman delete " pg_rman delete "2022-02-22 17:22:58""

三、清除備份集
物理刪除已從catalog刪除的備份集
上面從備份集中刪除的備份，備份集文件夾並沒有一起刪除。
[postgres@mxl ~]$ pg_rman purge

4 pg_rman 恢復

pg_rman 恢復默認原地恢復（覆蓋式），或者使用新的$PGDATA作為恢復目標。需注意如果在本機恢復pg_rman可能會覆蓋原有的數據文件arch,pg_xlog目錄中的文件, 可以先將原數據文件做下備份,默認pg_rman restore會在$PGDATA下產生recovery.conf根據實際需要修改相關恢復參數即可。 

1、recovery-target-timeline TIMELINE  
Specifies recovering into a particular timeline. If not specified, the current timeline from ($PGDATA/global/pg_control) is used. 
如果不指定時間線，則使用$PGDATA/global/pg_control，如果沒有$PGDATA/global/pg_control，則使用最新的全量備份集的時間線。 

2、recovery-target-time TIMESTAMP  
This parameter specifies the time stamp up to which recovery will proceed. If not specified, continue recovery to the latest time.
如果不指定，則恢復到最新時間  

3、recovery-target-xid XID  
This parameter specifies the transaction ID up to which recovery will proceed. If not specified, continue recovery to the latest xid.
如果不指定，則恢復到最新xid

4、recovery-target-inclusive
    Specifies whether we stop just after the specified recovery target (true), or just before the recovery target (false). Default is true. 
    是否在指定的恢復目標（true）之后停止，默認為true，如果指定false意識是在恢復目標之前停止

• The following parameter determines the behavior of restore.  
    --hard-copy  
    The archive WAL are copied to archive WAL storage area. If not specified, pg_rman makes symbolic link to archive WAL where are in the backup catalog directory. 
    是否使用硬鏈接復制archive log，如果不指定使用符號連接（軟連接）的方式。

#示例:  
    #pg_rman restore  --recovery-target-time "2022-02-22 17:25:30";  下面是沒有指定的恢復
    [postgres@mxl~]$ pg_rman restore 
    INFO: backup "2022-02-22 17:25:30" is valid
    INFO: the recovery target timeline ID is not given
    INFO: use timeline ID of current database cluster as recovery target: 5
    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: "2022-02-22 17:25:30"
    INFO: copying online WAL files and server log files
    INFO: clearing restore destination
    INFO: validate: "2022-02-22 17:25:30" backup, archive log files and server log files by SIZE
    INFO: backup "2022-02-22 17:25:30" is valid
    INFO: restoring database files from the full mode backup "2022-02-22 17:25:30"
    INFO: searching incremental backup to be restored
    INFO: searching backup which contained archived WAL files to be restored
    INFO: backup "2022-02-22 17:25:30" is valid
    INFO: restoring WAL files from backup "2022-02-22 17:25:30"
    INFO: restoring online WAL files and server log files
    INFO: create pg_rman_recovery.conf for recovery-related parameters.
    INFO: remove an 'include' directive added by pg_rman in postgresql.conf if exists
    INFO: append an 'include' directive in postgresql.conf for pg_rman_recovery.conf
    INFO: generating recovery.signal
    INFO: removing standby.signal if exists to restore as primary
    INFO: restore complete
    HINT: Recovery will start automatically when the PostgreSQL server is started. After the recovery is done, we recommend to remove        recovery-related parameters configured by pg_rman.

    pg_ctl start 

參考：

下載：https://github.com/ossc-db/pg_rman/
依賴包：https://yum.postgresql.org/10/redhat/rhel-6.7-x86_64/
使用手冊：http://ossc-db.github.io/pg_rman/index.html

來自為知筆記(Wiz)