64GB RAM Under 64-bit Linux?

gary.flake asks: "My group at NECI is in need of a machine that can address 64GB of ram in a single process. This means we need 64-bit addressing. We'd prefer to go with a Linux solution because all of our development is under Linux. We've spec'ed out some reasonable machines (Dell can do 32GB, and Compaq can do 64GB) but they seem to be lacking in that they can only be loaded up with 4 x 800Mhz Itaniums. We would really like to have more processing power (2 Ghz x 4 would be a dream). Does anyone know of any monster Itanium machines that will meet our needs? (Please, no Alphas). Finding such a beast is harder than you'd think."

Comments

Your Linux choices are Alpha, SPARC, and POWER.

[Anonymous Coward]

The ONLY 2 GHz processor available is Intel's 32-bit Pentium 4. 2 GHz or 64-bit; choose one but not the other.

Of course, Intel sacrificed a lot - particularly actual performance - for a high clock rate and thus the perception of speed from unsophisticated buyers.

The closest alternative is IBM's recently announced POWER4 systems, available in 1.3 and 1.6 GHz options. Extremely nice machines, which will blow the doors off a P4 with twice the clock rate, but if you have to ask about the price, the question is "merely profane, or really, really rude?"

Sun make plenty of machines that large, but their processors have always tended to trail in performance. They keep improving, but stay well behind the bleeding edge.

Alpha is the cheapest option, I think, but it's definitely end-of-life.

Additional options are SGI and HP, but you'd want to go with the vendor Unixes, because the Linux ports aren't ready for serious use yet.

Itanic is, to put it politely, not recommended for serious use. The Merced is a dog, and gcc doesn't help.

Some jobs do need 64GB RAM

[wmshub]

I can't believe the number of people implying that this guy is an idiot for needing 64GB RAM. People, not everybody uses their computer for browsing the web and playing Quake. There are some scientific applications out there, that are extremely important to people with lots of money, where having 64GB worth of fast-access matrices/hash table/etc. will let you do experiments that are simply not possible if you are limited to 1GB or if your data is on disk or across a network where access will be orders of magnitude slower than RAM. Give the guy a break, if he's seriously considering buying 64GB quad-itaniums, then I think you can assume that he has done the homework and figured out that it will be worth the money.

What surprised me is the "please, no alphas" comment. A bunch of alphas will have much higher performance than 4 itaniums. Yes, it is end of life'd, but when you are spending hundreds of thousands of dollars on your computer, worrying about the cost of porting to a new architecture when you replace this computer seems penny wise and pound foolish. Besides, as long as you are using the same OS and compiler on both old and new platforms, the "porting" should be mostly just a matter of recompiling.