oracle恢复时并行进程数增加，process参数需要调大，Media Recovery failed with error 448。

Completed: alter database recover datafile list
1 , 2 , 3 , 4 , 5
alter database recover if needed
start until change 1331285
Media Recovery Start
started logmerger process
Thu Feb 07 16:43:47 2013
Only allocated 107 recovery slaves (requested 128)
Parallel Media Recovery started with 107 slaves
Thu Feb 07 16:43:47 2013
Media Recovery failed with error 448