When we will do that upgrade I also want a dedicated raid controller and UPS installed. As im sure you know, a bunch of decent server disks, a good raid controller and a UPS = $$$
Personally I'd build such a server with ZFS (possibly run by FreeBSD). Some reasons why:
1. Free.
2. 100% reliability. Everything on disk is checksummed, and verified
by the CPU. It is practically impossible to get bad data from. This is not the case with RAID. A dedicated RAID controller can give you bad data.
3. Ability to back reads and writes with SSD's as cache, allowing use of cheaper spinning-rust while maintaining more than acceptable IOPS. In fact, you couldn't get that much IOPS from just a plain RAID controller and only spinning rust, even if the disks were expensive 2.5" 15k RPM.
4. When a dedicated RAID controller goes south, it can be both time consuming and difficult finding a replacement card, not to mention expensive. With ZFS you could in a worst case scenario replace the whole computer, plug the disks back in, and it would all "just work".
5. Power consumption. A dedicated RAID controller consumes power, and the 15k RPM "server grade" disks it most likely would be backed by also consumes a notable amount. This combines to require a larger cooling solution, which again adds some power consumption. This results in the need for a larger UPS, which of course drives cost up. With ZFS you can get 3 or 4 relatively cheap "green" spinning rust, and back them by 2 SSD's for caching.
A smaller UPS could run a properly configured system with what I had in mind by just a few config tweaks:
- UPS signals "Main Power Loss"
- Spin down the spindles, let writes queue up on the SSD (ZIL).
- Throttle CPU's, maybe even turn off all but 1-2 cores.
Depending on system, you could now be at a power-state requiring maybe 30W or less in total. A simple 300VA UPS could keep that system running at least 8 hours (unless my math skills have completely escaped me).
Compare this with a RAID card with (at least) 3 always-on 15k RPM disks. While the system throttling could be done, the controller and the disks would still be operating at their normal power. Larger and therefore more expensive UPS would probably be required for same uptime.
Anyway, I just wanted to bounce a few ideas that came to mind.
++luck;