Disk Separation DB installation and data files I am wondering whether it is a good idea to separate the database installation media from the actual data files.

In our current environment we have:


C: - Windows Server
D: - MS SQL Installation &amp; DB Data Files
E: - Backups
L: - Log files


Would it be a good idea to separate out our D: 


Drive 1: MS SQL installation
Drive 2: DB Data Files


There are similar questions already posted, but nothing specifically relating to the separation of DB software and DB data files. (similar questions ask whether it is a good idea to separate OS and DB).
Why do we separate things onto different disks?
Performance and resilience.  

From the Disaster Recovery perspective, if you lose any one of your disks, how much damage does it do? 

Lose the operating system disk?  OK, that's a biggy. :-(

Lose the backup disk?  Non-event; you still have a running database instance.  

Lose the data disk?  Ouch!  But that's OK; you've got your backups ... 
You just need to restore them into a running SQLServer instance ...  

Ah.  

But you had that on the same [data] disk that just failed, taking the data with it!  

Keep the installation and data separate. 

Whilst it's only semantics, I'd suggest keeping a closer "association" between the Data and Logs disks; they make up all the stuff you really care about. 

Move the backups off to another server altogether.  (Whilst it's unlikely these days) If all these disks are local to the machine and the machine's motherboard were to fail, it wouldn't matter how many disks you had; they'd all be gone!