Stuff & Nonsense

DIY Rack pt4

in 2021 I built a DIY Rack in my cellar (pt1, pt2, pt3). The last update on that is from a couple of years ago now, and looking back through the site archives I realise I never posted where that Journey ended……

At the end of 2021 I moved house. I knew that I wouldn’t have space for my little DIY Rack, so I’d have a couple of options. I could downsize, moving my kubernetes setup onto a couple of mini-PCs saving money on power and really not losing much in the way of performance given I was rarely utilising much of the 3 2U servers I had at this point. That was option 1, we’ll call that sensible option. Option 2 was….less sensible.

The house we were moving into didn’t, unfortunately have a cellar. it did however have a playroom for the kids. I really big playroom. For two small children. Surely they didn’t need all that space…..I could claim some of that space and put a proper rack in there. So in September 2021 I went from my 14u, relatively unobtrusive DIY rack to this:

a 24U, soundproofed RACK from APC. I got this for a (relative) steal secondhand, but it was still a pricey piece of kit and of course once you’ve invested in something like this, you’d be silly not to fill it right? So I went on a bit of a buying spree….

Yes, that is a bladecentre in the bottom there. Along with a 4u, 24 disk SAS shelf, a 1u hp server to serve that shelf, the 3 2U HP servers I already had, a couple of 1U UPS’ and then 2 more 2U UPS’ (unfortunately with duff batteries) right at the very bottom. There’s also a 10Gig switch in there somewhere. The blade centre I think ended up hosting 4 gen8 HP blades with a combined total of a couple of TB of RAM and 40 or so cores of Xeons.

Noise, temperature and power…. oh my!

That blade centre is where the real problems started. As well as being incredibly heavy (note: it’s really a 3 person job to move that off a van) it’s also very noisy and very hot and consumes a lot of power. I decided to tackle that first point first. Despite being billed as a sound proof rack and actually doing a decent job of dampening the noise produced by standard 1 or 2U servers, the APC was completely inadequate when it came to reducing the sound from the blade centre with its 10 high powered fans (seriously, these things are insane).

So, I needed some way of reducing the amount of noise produced by the fully stocked Server Rack I’d decided to install in a children’s play room. How could I do that…… well, if you said ‘get rid of the rack you absolutely numpty’ you’ve clearly not been following along. No, the obvious answer was to build a server room, with sound proof walls! Clearly.

I didn’t take many pictures of this process, I needed to get this server room built quickly before my wife realised what she’d agreed to……

Anyway, this actually worked pretty well. The sound was a barely noticeable hum most of the time, only rising to a very noticeably jet engine like roar when the blade centre booted. The second problem to tackle was heat. Luckily There was chimney breast at the back of this room, a chimney breast that a) was open to the sky at the top and b) no longer used for any fires. So I drilled a 6 inch hole into the chimney and another one very low down on the front wall of the server room, then with a couple of extractor fans and some air-con tubing I manager to rig up a pretty good system that sucked cool air in from the front, ran it through the rack and then pumped it out up the chimney.

It was still noticabley warmer in the server room than the rest of the house (which led to me pondering if I could recirculate the warm air through the house in winter…) but at least the servers weren’t cooking. Again, not many pictures of this process but….

That SDS drill is a beast by the way and also has a clutch mechanism, so when the core drill bogs down (and it will) the drill doesn’t wrench your arm out of its socket.

Finally, the third problem with having a server rack in your house; the electricity cost. Unfortunately, just as I finished building all this a situation kicked off in Ukraine, oil prices went through the roof and the knock on effect on electricity prices was…. not good. With a couple of blade servers, my storage, switches etc this setup regularly consumed 900w or so. Doing the calculations I worked out this was going to cost me a few hundred quid a month, which I couldn’t afford. So, with some regret, after all that work in march 2022 I went from the 24U rack, with a blade centre, terabytes of RAM, tens of terabytes of storage and more processing power than I knew what to do with to this:

A return to sanity

A single mini-PC, one switch, a power distribution unit I pulled from the rack before it went off to the scrappers and really not much else. After a few months I chafed at the lack of headroom and with a bit more tinkering in the summer of 2022 I finally settled on this setup:

2 mini-pcs, each with i5 processors and 16GB RAM running a kubernetes cluster. a 1Gig HP switch, an ubiquiti edge router and a PoE swithc to run my wireless access points. This consumes about a tenth of the power the rack did while providing all of the same services with little performance drop. My one problem now is storage, you’ll notice the lack of any network attached storage here. But for that, I have a cunning plan…

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