Windows vs Unix

[Former Member]

My site is discussing the possibility of moving our SAP/R3, Oracle DB instances from Solaris8 servers to Windows servers when we get $ for our hardware within the month. I am in favor of staying on unix/solaris servers, but others want Windows servers. I know that window servers are cheaper, mostly I am concerned about performance issues between the two.

Has anyone done this and if so, what are your SAP/R3

experiences...i.e. system performance on unix vs windows, other OS issues , etc. ?

[Former Member]

We had Windows before (NT 4.0 EE and 2K) and moved to Linux two years ago. Now we're running ~ 800 Users (600 concurrent) on 5 application servers against a MaxDB Database and we don't have any problems.

[eddy_declercq]

Hi, We have a lot of SAP R/3 EE (HR, PM, CM, FI, etc.) and Netweaver running on AIX/Oracle. We have about 8000 users and it works well. The only problem is SAP itself when they release new versions of eg Netweaver. One can have wait for a long time before something is released for a specific Unix flavour. Windows is always served first. One said to me at Teched that this would change when the Linux release is coming to bigger proportions.

Eddy

[eddy_declercq]

Hi,

Pls don't forget to give reward points if you feel that your question is answered.

Eddy

[gregorw]

Hello Rose,

how large is you installation?

What OS is used on the clients? If they only use Windows and authenticate on an Active Directory it is good when you migrate your SAP infrastructure to Windows because then you can use Single Sign On.

Regards

Gregor

[Former Member]

please compare perfomance of the latest window; unix operating systems

[eddy_declercq]

Can it be compared performance wise? I would say that all depends on the machinery available. Stability is also a key factor.

[Former Member]

Hello

"Windows vs. Unix" is a difficult question to seperate fact and opinion.

Today Operating Systems and Databases have commoditized in terms of features, stability and performance.

OS and DB have not commoditized in terms of price however. Unix/Oracle and mainframe are the most expensive platforms to run SAP on. There are cheaper and better options. The commercial relationship between SAP and Oracle is not too good and this is impacting the merits of running SAP on Oracle.

Oracle itself is a good database, however last time I checked SAP were still delaying official support of 10g over two years after it was released!

SAP is an application that has been ported to many different operating systems (HP-UX, Solaris, Windows, zOS for the mainframe etc). To a large extent SAP <b>does not</b> utilize specific functionality of a particulary operating system or database.

Logically speaking, how could SAP be a truely multi OS application that will run on everything from a IBM zSeries mainframe to a desktop PC running Windows if it was <b>highly optimized for any particular OS</b>. SAP would go bankrupt developing and supporting so many different platform combinations. (remember a platform has multiple DB combinations such as AIX Oracle, AIX DB2, AIX MaxDB).

There is very poor understanding in the SAP community of the recent developments in regards to Windows (particularly amoungst those who work with Unix).

Historically Windows has not be an option for a site with more than ~500 users because Windows was a 32bit operating system and the Intel x86 (386, 486, Pentium etc) processor was a 32 bit.

A 32bit processor has performance limitations regardless of the operating system. 32 bit HP-UX or AIX would not be suitable for large sites, neither was Windows until recently.

A 32bit platform is limited to 4GB of memory (2^32). Windows had a way to try to utilize more than 4GB by mapping memory (AWE) but it was not very useful. With only 4GB of memory available you will typically find that your OS will start paging to disk and slow down.

Fortunately there are now two different 64bit versions of Windows available in addition to the 32 bit version. There are special limitations regarding the use of these operating systems in an SAP context.

In total there are now THREE distinct versions of Windows:

1. Windows IA32 - traditional 32 bit Windows, no useful ability to utilize more than 4GB RAM - everyone is familiar with this one

2. Windows x64 - utilizes the 64 bit extensions first introduced by AMD and then Intel - this version of Windows CAN utilize more than 4GB of RAM if the program has been compiled for x64. If a program has not been compiled for x64 it is generally given a complete 4GB address space to run in. IA32 and x64 are compatible, you can even install Windows IA32 on a x64 chip and it will run very fast. So this version of Windows is "backward compatible" you could say, as it runs IA32 applications and new x64 applications.

3. Windows IA64 - completely different version of Windows compiled for the Itanium chip. The itanium chip is most often found in large HP-UX servers and is very often used for running large SMP Unix/Linux systems. Microsoft ported Windows 2003 to Itanium in 2002/3 and Windows runs very well on this platform. The chip is a complete redesign and is not based on an x86 instruction set. As it result you cannot run IA32 executables effectively. If you application is not compiled for IA64, then forget about running it on an IA64 system. This platform is excellent for large sites.

SAP support all versions of Windows (IA32, x64 & IA64) to varying degrees. IA32 is very common, but is not a good solution for SAP since it has a performace limitation due to the memory address space restrictions. All SAP components I know of run on IA32 however.

Most ABAP components are NATIVELY compiled for x64, the Java components generally are not natively compiled but will run as IA32 applications very well (fast & stable).

Most SAP components ABAP and Java are NATIVELY compiled for IA64 (at least for Win SQL IA64 which is the platform we run - check PAM for other DB - there are restrictions on Oracle). SAP applications run very well and very fast on Windows IA64. Stability is also very good.

Database and SAP related benchmarks show no significant differences between Windows and Unix:

http://www.tpc.org/tpcc/results/tpcc_perf_results.asp?resulttype=all (check #3 on the list)

http://www50.sap.com/benchmarkdata/sd3tier.asp (over 96,000 users benchmarked on Windows SQL Itanium)

With a Windows environment you do need to block access to your servers with a firewall/SAP Router/VLAN/Web dispatcher or some other mechanism. A well designed Unix environment should follow a similar network design as well.

There are some limitations with MSCS which you need to overcome with third party software. HP offer a good solution for HA.

Stability is dependant on your hardware. In the case of HP Windows Itanium servers there is no difference whatsoever between the server hardware for HP-UX and Windows. In fact you can have Win2003 running in one partition and HP-UX in another.

You do need to ensure that your Windows support people are disciplined in regards to change control on the OS, however this is also true of Unix platforms.

IA32 and x64 hardware is generally of a lesser quality unless you buy from the larger vendors such as HP and IBM

Hope some of this is informative. The TCO case for moving to Windows is compelling if you do the numbers, it will pay for itself very quickly.

[tim_buchholz]

Dear Rose,

I can only second Sam's remarks. The main drawback in classic Windows is its 32-bitness. If you go for a 64 bit installation, the performance achievable will depend on what hardware you supply.

Regards,

Tim