一、问题描述
由于服务器配置不高，备份策略为周末全备、周一至周六差异备份。
平时服务器CPU使用30%左右。
全备份时，开启两个通道，CPU达到90%左右，业务部卡顿、不掉单，session不积压，磁盘读取200MB/s
差异备份时，开启两个通风道，CPU达到100%，业务卡顿、掉单，session积压,磁盘读取200MB/s
二、控制RMAN的备份时间--duration和关键字minimize load
限制rman备份时间在5min以最小负载方式完成，语法如下：
RMAN> backup duration 00:05 minimize load database format '/home/oracle/backup/%U.dbf' ;
三、控制RMANIO消耗--rate readrate
控制差异备份IO读取速度
run{
crosscheck backup;
delete noprompt expired backup;
allocate channel d1 type disk maxpiecesize = 3500M rate 20M; ----设置磁盘读取为20M/s
allocate channel d2 type disk maxpiecesize = 3500M rate 20M;
#crosscheck archivelog all;
#delete noprompt expired archivelog all;
#crosscheck backup;
#delete noprompt expired backup;
backup incremental level 1 as compressed backupset database format '$backdir1/full_%d_%T_%t_%s_%p';
sql 'alter system archive log current';
backup as compressed backupset filesperset 10 format '$backdir1/arch_%d_%T_%t_%s_%p' archivelog all;
backup current controlfile format '$backdir1/ctl_%d_%T_%t_%s_%p';
release channel d1;
release channel d2;
#report obsolete;
#delete noprompt obsolete;
}