separate physical hard disc?该如何处理

separate physical hard disc?
Iwant to ask
 is there any advantage for putting all related data in a separated physical database? ( if a single HDD fail (if it is not in RAID), other Data in another HDD can be kept )
Take for example, put all invoices into one separate physical database?

thanks

[解决办法]
没有安全性的久没有任何好处.
在某些RAID中,坏掉其中一个硬盘不会丢失数据的.