PowerVault NF500 upgrade options

What do you mean they have a different number of channels?  All PERC 6 cards have two channels (so does the SAS 6/iR for that matter).

You can pretty much organize the disks on the channels however you like.  You can separate different RAID volumes on different channels, which may give you a performance bump likely only seen on benchmarks.  However, the RAID controller is also perfectly capable of managing a RAID array whose disks are spread across both channels.

If you feel comfortable with a non-redundant RAID 0 for your OS, then there is nothing technically wrong with running the configuration you describe (single-disk RAID 0 and 5-disk RAID 5 or 6).

"Is there anything special about the drives I need to specify?"

Not sure if there is anything specific here you are wondering about, but you should avoid cheap consumer/desktop drives, as they are unsuitable for use on an enterprise-class RAID controller.  Your drives should be enterprise/RAID class drives, and preferably, should be certified for use on the PERC (Dell branded enterprise-class drives) and can be SATA or SAS (NL-SAS).

Thank you again, Flash. You've been most helpful. I really do appreciate your willingness to share your knowledge and experience with someone like me who is obviously a noob.

I'm going to give my boss 4 options -

1) Upgrade to PERC 6/i and 2TB drives

2) Upgrade to H700 and 3TB drives

3) Add MD1200

4) Replace server with NX3200

I'm pushing for option 4. It's actually less expensive than #3, will probably perform better and leaves room for expansion.

Flash,

One more question. I'm not having any luck finding a 3rd party vendor of Dell certified drives. Can you tell me what I should be looking for?