A few comments from my perspective... while I'm not a huge fan of the 4 systems in 2u boxes, a lot of them are more dense, power-wise, than 1u boxes (at least in my experience - ours used shared power supplies, which helped) and so that makes up for some of the frustration (but also means that if one locks up, hard, you can't just do a remote power cycle if you have a 'smart' power strip).
What I will say, though, is that if anyone is considering blades, I'd seriously consider Seamicro: http://seamicro.com/SM15000 This is an unsponsored, non-employee plug: I used one of their systems for several months at my last job, and I loved it. It was ridiculously dense, easy to manage, and worked well. It's basically like the ultimate blade server; 64 discrete systems in 10u, plus separate blades for shared storage (although you can provision enough that it doesn't actually have to be shared) and shared networking. It's not for every application (no more than a single socket per blade, although the RAM goes surprisingly high) and I think it maxes out at something like 16 x 10G ports, but for what we were doing it was great. And our full chassis used (depends on the blades you get, obviously) something like 16A @ 208V, meaning even w/ redundant power you can get 64 systems using only 2 x 20A circuits. Disclaimer: they were recently acquired by AMD; I can't vouch for how AMD will run the company now, but Seamicro as a stand-alone company was awesome. Nicholas On Wed, Apr 3, 2013 at 2:46 PM, Matt Lawrence <[email protected]> wrote: > This is a bit of a rant, so adjust your filters accordingly. > > I'm currently doing some work not really production datacenter (unless you > ask the developers) that has a variety of systems. Some of the systems I'm > dealing with are the 4 servers in 2U variety. It's a neat idea, but great > care needs to be taken to avoid problems. One of the big issues is cable > density, the systems I'm managing have a BMC connection, 2x 1Gb > connections, 2x 10Gb connections and a KVM dongle. That's 7 things plugged > into the back of each server (KVM is VGA + USB). Multiply times 4 and > that's 28 cables per 2U, plus 2x power cables. That's a lot of cables and > they aren't running in neat rows like a 48 port switch. > > Adding to the problem is the fact that the disks plug in to the front of > the system and the server electronics plug in from the back of the server. > Right through that rat's nest of cabling. It's a challenge. If you > consider yourself ok at cabling, you don't have anywhere near the skills to > do cabling at this density. Typical cabling standards are not adequate for > these kinds of setups. Mediocre cabling also really blocks the air flow, > the systems I'm dealing with are nice and toasty at the back of the cabinet. > > Another option I'm dealing with are blade enclosures. They manage to get > 16 servers into 10U of rack space and (at least here) they have switches > built in. This means I only have 7 network cables running to a top of rack > switch/patch panel. So much easier to deal with. The blades are > accessable via the front of the rack, which is also much easier. The > enclosures have built in management, which again makes things easier. A > downside is that certain failures require taking down the entire encloser > to fix, so you lose 16 servers instead of the 4 in the other kind of high > density server. I have never ben a big fan of blade enclosures, but I'm > starting to come around. > > Of course, one issue that too few people think about until it is too late > is the issue of power density and cooling capacity. Being able to put 4 > servers in 2U sounds really nifty until you discover you can only power and > cool half a rack of them. > > This concludes my rant for today. Maybe. > > -- Matt > It's not what I know that counts. > It's what I can remember in time to use. > ______________________________**_________________ > Tech mailing list > [email protected] > https://lists.lopsa.org/cgi-**bin/mailman/listinfo/tech<https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech> > This list provided by the League of Professional System Administrators > http://lopsa.org/ >
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