使用rman duplicate创建DG备库时开并行

duplicate加并行：

run
{
allocate auxiliary channel c1 type disk;
allocate auxiliary channel c2 type disk;
allocate auxiliary channel c3 type disk;
allocate auxiliary channel c4 type disk;
allocate auxiliary channel c5 type disk;
allocate channel c6 type disk;
allocate channel c7 type disk;
allocate channel c8 type disk;
allocate channel c9 type disk;
allocate channel c10 type disk;
duplicate target database for standby from active database nofilenamecheck;
release channel c1;
release channel c2;
release channel c3;
release channel c4;
release channel c5;
release channel c6;
release channel c7;
release channel c8;
release channel c9;
release channel c10;
}