IBM Announces First Linux-only Mainframes

A reader writes "The new Z-series mainframe for Linux, which costs $400,000 and is aimed at processing transactions at large businesses, is IBM's first mainframe computer sold without IBM's traditional z/OS mainframe operating system. More info at the IBM zSeries page" This is something that IBM and others of Big Iron vendors of *NIX have said - as Linux grows in maturity, they want to replace their *NIX with Linux. However, there's still work to be done in that area.

Re:Relative costs?

[blackcat++]

Well, the first part of cost savings are not Linux-specific. You just save a bundle :-) by not having to care for 20 different NT/Solaris/etc. servers, but only for one piece of hardware. Using Linux to run the multiple virtual servers saves licensing costs and enables you to hire one of the many Linux admins out there to set them up.

Re:Relative costs?

[Geeky]

I don't think it's supposed to reduce the cost of a $400,000 machine, but allow that $400,000 machine to replace 50 $8000 machines.

As for cost of ownership, does the lack of a mainframe OS mean the loss of abilities like being able to back up the entire machine (all the virtual Linux servers) at once? The big win of Linux on mainframe is central management of dozens of virtual servers, plus the fact that each server is completely independent.

I was under the impression that the mainframe OS still played a role in managing the virtual machines. A Linux only mainframe would seem to imply a single system.

Re:Relative costs?

[PoiBoy]

Perhaps this is true, but $750k for a mainframe still doesn't buy much of anything. My understanding is that to purchase all the hardware for a new mainframe installation will set you back at least $5 million, not including on-going service contracts.

I'm tempted to take this $400k figure with a huge grain of salt. I'm not sure that will get you much of anything except, perhaps, the main CPU box with one or two processors. I'd bet the total cost of installation is much higher.

Re:Relative costs?

[Carl Drougge]

but how much does using a linux reduce the price of a $400,000 machine?

I don't think it's supposed to. I think it's supposed to make maintaining a workabe OS for the mainframe cheaper for IBM.

The mainframe CPU is not slow

[bunyip]

MIPS = Meaningless Indicator of Processor Speed

The mainframe is MIPS per CPU, so the 16-way box is 16*120. Also, 120 MIPS is slow these days for a mainframe.

Write a simple memory intensive program and try it on a mainframe and try it on a PC. I guarantee that you won't get 3000 MIPS out of a desktop, even if the data fits in cache. Many reasons for this....

The s390 ISA is definitely CISC, you can copy a whole string with MVCL, that count's as one instruction. Do this on RISC machines and it might take a loop and execute dozens of instructions. Hence "Meaningless ..."

About 2 years ago I wrote some C code to recursively quicksort 20M random integers and tried it on a bunch of platforms. A mainframe that was about 1 cycle behind fastest available gave me about the same single processor performance as a 1GHz PC, both a little slower than Alpha.

The big differentiator is memory architecture. How much time do you lose for a cache miss? Most processors only operate at 20-30% of theoretical maximum speed on big problems.

Memory speed has not kept up, that 2GHz box you dream about is not twice as fast as a 1GHz box, particularly if you're crunching a lot of data.

Article here...

[Juju]

Here is an article of a company switching it's infrastructure to Linux planning to ditch 70 netfinity servers as well as 500 NT servers in the process. The cost of the 500 NT servers only should cover that of the mainframe.

But most their savings are due to improved scalability and easier maintenance (especially for disaster recovery).

Read the article, all the arguments for the switch are there.
Store chain is sold on Linux [ZDNET] [zdnet.com]

Re:Nobody ever got fired for buying IBM

[Fjord]

A previous netcraft survey [theregister.co.uk] backs your claim up, this is a trend:

Linux is the second most commonly used operating system. Linux has been consistently gaining share since this survey started, but, interestingly, not significantly to Windows detriment. Operating systems which have lost share have been Solaris and other proprietary operating systems, and to a small degree BSD.

Wrong

[s390]

The average 16 processor mainframe is a 120 MIPS machine, whereas the average 1.5 GHz desktop system is a 3000 MIPS machine.

Mainframes run up to about 200 MIPS per processor and with multi-processor overhead a 16-way zSeries tops out somewhat below 3,000 MIPS. These are mainframe MIPS, not what you get as BogoMIPS out of Linux at boot (AFAIK, this is some quick integer timing loop calculation). There's a reason it's called BogoMIPS, troll.

IBM has successfully run over 40,000 Linux images on a mainframe (under VM). Try that on your 1.5Ghz desktop. Ever heard of Transactions Per Second (TPS) in four and five figures, I/O rates in GB/sec, multi-terabyte databases, 99.999% uptime for years? That's mainframe territory, and I sincerely doubt that you've ever seen it, or ever will.