RMAN-06091 no channel allocated for maintenance

系统：CentOS7.4

数据库：11.2.0.4

run块语句如下：

run{
allocate channel c1 device type disk;
allocate channel c2 device type disk;
allocate channel c3 device type disk;
report obsolete;
crosscheck backup;
delete noprompt obsolete;
backup as compressed backupset database format‘/dbbak/db_%U.bak’ plus archivelog format ‘/dbbak/arc_%U.bak’;
backup current controlfile format ‘/dbbak/ctl_%U.bak’;
delete noprompt archivelog until time ‘sysdate-14’;
release channel c1;
release channel c2;
release channel c3;
}

异常描述：在执行rman备份时，报错RMAN-06091，如下所示：

造成此异常是由于rman备份通道被调整为非磁盘通道所致，而默认的通道为磁盘通道，所以delete noprompt obsolete命令不会成功.

查看当前rman通道设置：

RMAN>show all;

CONFIGUREDEFAULT DEVICE TYPE TO DISK; # default

解决方案：

方案1：

在run块外添加allocatechannel for maintenance type disk;

方案2：

在run块里的delete后添加devicetype disk，如下：

delete noprompt obsoletedevice type disk;

delete noprompt archivelog until time ‘sysdate-14’device type disk;