在oracle的database目录存在一个hc_orcl.dat文件，orcl应该表示oracle_sid.google发现如下链接：
http://forums.oracle.com/forums/thread.jspa?threadID=309881
HC stands for a health check monitoring.
It contains information used to monitor the instance health,
and to determine why it went down if the instance isn't up.
The file will be recreated at every instance startup.
You don't need to back it up.
