Oracle数据库软件标准版的一个限制：仅仅能用一个rman channel
Oracle数据库软件标准版的一个限制：仅仅能用一个rman channel
Restrictions in "Standard Edition" Rman channel allocation does not allow parallelism/having multiple channels allocated.
来源于：
RMAN DUPLICATE FROM 'ACTIVE DATABASE' in "Standard Edition" fails with RMAN-6181 (文档 ID 1265014.1)
