From owner-chemistry@ccl.net Sat Oct 1 02:09:00 2005 From: "Perry E. Metzger perry^piermont.com" To: CCL Subject: CCL: W:hardware for computational chemistry calculations Message-Id: <-29445-051001000949-7785-Resn48DJ0cTAGIuSoT3MXg|server.ccl.net> X-Original-From: "Perry E. Metzger" Content-Type: text/plain; charset=us-ascii Date: Sat, 01 Oct 2005 00:09:46 -0400 MIME-Version: 1.0 Sent to CCL by: "Perry E. Metzger" [perry]![piermont.com] "Igor Filippov Contr igorf[]helix.nih.gov" writes: > Sent to CCL by: "Igor Filippov [Contr]" [igorf|*|helix.nih.gov] > Excellent advice. I would agree with everything, except for the "buy > Dell" part. If you've bought Dell (and probably any other named brand > PC) - be prepared that it won't be upgradable, Well, do the economics. It isn't worth upgrading machines any more. Generally after a couple of years you need to replace effectively everything in order to upgrade. My usual advice to an organization is to assume that machines should be cycled out very fast. You are better off (if you're doing high end computation) buying fewer, cheaper and slower machines and replacing them all every year than buying more ultra-fast boxes every three or four. Why? The fastest possible boxes are usually very poor price/performance -- you can pay 50% more for only a few percent extra oompfh. If you're doing parallel computation anyway, you really only care about cycles per second across the cluster per dollar, not cycles per second per box. If you set an annual budget, and buy and replace portions of your compute cluster every year (or turn last year's compute cluster into the "lower end" cluster every year until you run out of room/power and get rid of them), you will never have as fast a cluster as your neighbor in year one, but he'll be way envious of you in year three when his machines are maybe a factor of 6 slower than yours. I suggest that organizations budget what they are willing to spend annually on their compute cluster and go for the best price/performance boxes each year in the quantity they can afford. Next year's machines will do twice as well for you, and you will be able to buy them next year instead of waiting three years. Of course, doing the math yourself is advisable. The exact time frames, difference in price/performance between the top and not quite top end machines, etc. shift very fast. My only point is, keep in mind that computers are not forever, and Moore's Law is an exponential curve, so given that you're going to replace them eventually anyway, try to treat them more disposably. > and after this particular model goes out of fashion it won't be > repairable either. Dell does pretty well on repairs during their couple year repair period. After that, you should probably replace if you're using the box for compute bound work. > Their cases are a nightmare to disassemble As I said, though, if I was buying more than 2 or 3 boxes (or if I was buying 2 or three high end AMD64 boxes) I wouldn't buy Dell any more. If you only have that many boxes, however, you might as well let the Dell people service the machine -- you can't afford enough spare parts on hand yourself anyway. I have to say, though, I have a bunch of Dells and their 1U and 2U boxes seem just fine to me in terms of ease of disassembly. Two thumbscrews and the lid just comes up. If you're talking about non-rack mountable cases, well, I don't buy those for servers or compute farms. Maybe they are a nightmare, but I don't buy 'em so I don't see 'em. > I would suggest buying things from a small-time vendor that: > a) uses only non-proprietary components - i.e. case, power supply, etc. > that you can get at any CompUSA or BestBuy if you ever need to replace > them. The principle is reasonable, but you'll never get power supplies etc. that will fit in rack mount cases at CompUSA. They simply don't sell them. I usually get stuff like that online from NewEgg. > This way you'll get exactly what you designed yourself and you'll be > able to repair/upgrade/modify it by using a simple Philips screwdriver > and parts that you can get at any computer store. And it will be cheaper > too - I'm more than a little surprised about the talk about "cheap > prices at Dell" - go to pricewatch.com you can find tonnes of places > with better deals, where you don't have to pay for the "Dell" sticker on > your computer case. Last year, I was looking for a pair of new 1U servers. I got a couple > from Dell for $700 each. None of the white box guys would sell me identically configured for less than $900. Now, I didn't buy the memory from Dell -- they squeeze you for all they can on that (how do you think they sell the base systems so cheap?), and so I always buy > from Crucial instead -- but the boxes themselves were unbeatable. Right now they're selling deskside boxes with amazing configs for like $300, which for a poor chem department that could not afford better would be a steal. BTW, keep in mind, I do *NOT* advise buying Dell if you're getting anything in quantity or anything "serious" and keep in mind that they do NOT do AMD64 stuff, so if you need better than bottom end, you can't buy from them anyway. Mostly I recommend them to people who need a good $300 or $800 box, can't do the maintenance work themselves and don't want the fuss. -- Perry E. Metzger perry..piermont.com