怎么理解定時任務crontab

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腳本目錄：

• [oracle@tangjian ~]$ mkdir -p /u01/app/oracle/rman/scripts/

歸檔目錄：

• [oracle@tangjian ~]$ mkdir -p /u01/app/oracle/rman/arch/

創建腳本：（每月一次0級增量）

• [oracle@tangjian ~]$ vi /u01/app/oracle/rman/scripts/full_backup_run.sh

#!/bin/bash

#Usage:test database hot full backup !

export PATH

export ORACLE_BASE=/u01/app/oracle

export ORACLE_HOME=$ORACLE_BASE/product/11.2.0/dbhome_1

export ORACLE_SID=test

export PATH=$PATH:$ORACLE_HOME/bin

DATE=$(date +%Y%m%d)

mkdir -p /u01/app/oracle/rman/$DATE

rman target / <<EOF

run{

allocate channel c1 type disk;

allocate channel c2 type disk;

sql'alter system switch logfile';

crosscheck archivelog all;

delete noprompt expired archivelog all;

backup incremental level 0 database format '/u01/app/oracle/rman/$DATE/test_%U.bk' include current controlfile plus archivelog delete input format '/u01/app/oracle/rman/arch/arch_test_%U.arch';

crosscheck archivelog all;

delete noprompt obsolete;

delete noprompt backup of database completed before 'sysdate - 32';

release channel c1;

release channel c2; }

exit;

EOF

• [root@tangjian ~]# chmod -R 775 /u01/app/oracle/rman/scripts/full_backup_run.sh

添加定時任務：

• [oracle@tangjian 20180730]$ crontab -e

#rman backup full database shell

52 14 * * * /u01/app/oracle/rman/scripts/full_backup_run.sh 1>/u01/app/oracle/rman/rman_backup_full.log 2>&1

查看任務列表：

• [oracle@tangjian 20180730]$ crontab -l

創建腳本：（每星期一次1級差異增量）

• [oracle@tangjian ~]$ vi /u01/app/oracle/rman/scripts/level_backup_run.sh

#!/bin/bash

#Usage:test database hot full backup !

export PATH

export ORACLE_BASE=/u01/app/oracle

export ORACLE_HOME=$ORACLE_BASE/product/11.2.0/dbhome_1

export ORACLE_SID=test

export PATH=$PATH:$HOME/bin:$ORACLE_HOME/bin

DATE=$(date +%Y%m%d)

mkdir -p /u01/app/oracle/rman/level/$DATE

rman target / <<EOF

run{

allocate channel a1 device type disk;

allocate channel a2 device type disk;

sql'alter system switch logfile';

crosscheck archivelog all;

delete noprompt expired archivelog all;

backup incremental level 1 database format '/u01/app/oracle/rman/level/$DATE/test_%U.bk' include current controlfile plus archivelog delete input format '/u01/app/oracle/rman/arch/arch_test_%U.arch';

crosscheck archivelog all;

delete noprompt obsolete;

delete noprompt backup of database completed before 'sysdate -32';

release channel a1;

release channel a2;

}

exit;

EOF

• [root@tangjian ~]# chmod -R 775 /u01/app/oracle/rman/scripts/level_backup_run.sh
  

添加定時任務：

• [oracle@tangjian 20180730]$ crontab -e

#rman backup full database shell

00 1 1 * * /u01/app/oracle/rman/scripts/full_backup_run.sh 1>/tmp/rman_backup_full.log 2>&1

#rman backup level database shell

00 1 * * 7 /u01/app/oracle/rman/scripts/level_backup_run.sh 1>/tmp/rman_backup_full.log 2>&1

驗證腳本可用性：

• [oracle@tangjian scripts]$ sh full_backup_run.sh

• [oracle@tangjian scripts]$ sh level_backup_run.sh

常用命令：
/sbin/service crond start           啟動服務

/sbin/service crond stop            關閉服務

/sbin/service crond restart       重啟服務

/sbin/service crond reload        重新載入配置

在/etc/rc.d/rc.local這個腳本的末尾加上（開機自啟）：

/sbin/service crond start

crontab -u        設定某個用戶的cron服務，一般root用戶在執行這個命令的時候需要此參數

crontab -l         列出某個用戶cron服務的詳細內容

crontab -r        刪除某個用戶的cron服務

crontab -e        編輯某個用戶的cron服務

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