Why not try looking at this differently? You think £100 is an OK hardware budget and cost of powering the server as an ongoing isn't important to you. Obviously depending on the spec of the server in question and what you pay for power this will vary, but here are some numbers:
http://i.imgur.com/Ly13Zvt.png
That's from an actual DL180 G6 at idle, your spec may differ, but it's 209w/hr average according to onboard iLO, using my own power figure (based on my usage inc standing charge courtesy of my Loop) I have 14.33p/kwh, that's gives us just under 3p/hr, 72p/day, £262/yr. so your Y1 cost is £362 + caddies (can take up to 12 from memory?) so let's round it to £400 in Y1. HP lock down updates on commercial stuff which is problematic, they also go into crisis mode with non HP cards installed, fans to max etc. which exacerbates the noise/power issue.
With £400 to spend you could easily buy a few 6-8TB drives and power them, as you mention you have multiple other PC's/servers you could virtualise your 2k16 install and for bugger all extra power have very similar end results with way more storage. If you prefer to go with a physical build, then a consumer x99 set-up is likely to set you back £240ish (2630L/x99 board/8GB/Antec 900/H310 HBA, 3 x 4in3 backplanes), that's 12 bays plus spare SATA for SSD's for VM's/cache and the option of a 13th drive mounted in the base for 20/bay based on 12. Those numbers are based on what I personally paid a few months back. I had a PSU/GPU and SAS to SATA cables, but either way it's a very capable virtual environment and file server with 8c/16t. Looking at the idle power consumption (can't remember if this was before or after fitting the HBA) it was approx 50w or less measured at the socket, put another way it's less than 1/4 of the DL180, it's also quiet enough that it could - and did - live in the lounge, heat output is also minimal. In my example (and remember I had a PSU/GPU) i'm roughly £100 better off in year one with a vastly more capable system and by year two it's getting on for £300 total saving just on idle numbers, if you intend on actually using it for anything, then the savings at load are even bigger (x99 load was circa 100w) and the performance vs anything you'll find in a DL180 G6 is huge.
This probably isn't what you want to hear, but at least think about it, it's madness to pay £400 in Y1 and a combined £662 in Y2 just to access a few 160GB drives, thats plus the power for the drives and plus the workload of actually doing anything else on the box.
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