SAP, Itanium, Linux and virtualization ...

Question

If you've been there, these keywords without Linux usually lead to HP-UX and HP VSE OE with Integrity VM. But, if you try to find legitimate and practical alternative, it turns out that RHEL with Xen is the only good choice.
I have several system copies running on RHEL5.4 Linux with Xen virtualization platform, most of them are SAP ERP based with Oracle 10.2.0.4, ECC 6.0 EhP3, both on HVM Windows Server 2003 guest systems and on PV RHEL5.4 guest systems, few IDES systems, one with NW7.0 and Portal. All this is running on HP Integrity / Itanium 2 hardware (BL870c), and FC SAN, HP EVA 5000 and EVA 8400 is used for storage. What I'm interested here above all is to hear if there is anybody out there having some similar story (SAP, Itanium, and virtualization) ? Please, speak out if you are listening ...
I have some documents prepared and in preparation with details (I will put it here or in blog if there is interest), but for now just in short: systems are quite good, performance could be compared with some physical systems and production servers, but above all it is very stable. We also use VMWare for x86/x64 in our company, so I am able to compare these two platforms. There are many pros and cons, but I think that both offer good solutions. One of the main conclusions is that Xen on Itanium compared to HP-UX offers similar if not even better performance (that is, at least until HP finally gets implemented AVIO for HVM Windows guests), and if you are not in need of some high-end features (including live migration), Xen is better. There were some bumps on the road, though - Oracle showed me a bug (some workaround is available, though), but the biggest of them all is that RHEL decided to abandon support for Itanium in RHEL 6 ... SLES is a good option, but it is not supported by SAP at the moment. Any comments, questions, hints, insights, advice ?
ZP.

Answer 1

>
Markus Doehr wrote:
> All other vendors (Bull, Unisys, Dell, IBM...) abandoned IA64 because it's too expensive (too few numbers of them)  and too slow; the cost/performance ration is miserable, the x86 32bit compatibility mode is much slower than expected. You have to spend a lot of money for an e. g. 4-way box; for the same money you can buy an even more powerful x86_64 system or two of them.
> Markus
I ment, not just hardware vendors (Oracle, Microsoft, SAP, ...) - IBM had the most performant system based on SAPS and benchmarks for long time (AFAIK, if it didn't change in the mean time, Oracle also made a competition, I don't know if anyone took the claim), but it had even worse cost/performance ratio than HP Integrity. If you want high end performance, Itanium can give you solid single-threaded horse power that x86 couldn't offer (again, AFAIK), and this is very important for databases and some business systems - it is not always about parallelization and number of concurrent users per system.
>
Markus Doehr wrote:
> Itanium is due to its design best suited for technical/scientifical (floating point) processing, not that much for integer processing (what SAP basically does - including the databases) or for running virtual machines (ABAP/Java).  Because of the nature of it being an EPIC processor all the optimization logic must be put into the compiler. I guess, the open source community will not be able (just due to the lack of manpower and knowledge) to make gcc as good as the HP-UX aCC compilers.
>
> We have and had several Linux/IA64 boxes which were replaced by x86_64 (mainly AMD). For half of the price you get at least the double throughput; IMO there's no more justification for preferring iA64 over x86_64 any more.
> Markus
Unfortunately or not, my management decided to move on with Itanium (but unfortunately for sure they decided years ago to go into production with Windows). You are right up to some point - Itanium is EPIC, but it is not just for scientific and FP, why would they've been sold successfully as platform for database servers for years ? There are IA64 CPUs with additional FPU and cache, and there are different versions and platforms - what did you exactly compare ? Generally it's still not that clear IMO. And here comes my favourite anegdote about Itanium raw performance: while doing an Oracle 10g patch (CPUJan2009 bundle, I think or something like that), carelessly for some reason (I usually don't do it that way, of course) I haven't read the patch README and I have omitted to do additional view compiling by habit (many patches/patchsets do not need it beside the usual compiling). Production database node has two dual 1.1GHz processor modules and 8 or 16G of RAM at that time (mx2 modules, let's say it is like 2 CPUs with dual cores), and the moment I have had database ready for use I have concurrently read that I need additional compiling which needs about 30 minutes for average database with 2000 objects by internal Oracle benchmarking/testing. I have sighed, did query and saw three to four times more objects in my database than stated in the README manual, and started swearing in myself about complicated corporate procedures and flows about informing users, system availability, internal QA, etc. So, I decided to put system back down with my teeth strongly clenched together and started these two scripts on production system (not the usual situation, I repeat). It lasted not more than 5 minutes ! I didn't have to follow all the strict QA procedures, inform users, and so on ...