Best Practices for zVM/SLES10/zDB2 environment for dialog instances.

Hi, I am a zSeries system programmer who has just completed an IBM led Proof of Concept which demonstrated the viability of running SAP instances on SUSE SLES10 Linux booted in zVM guests and accessing zDB2 data via hipersockets. Before we build a Linux infrastructure using the 62 IFLs we just procured, we are wondering if any best practices for this environment have been developed as an OSS note or something else by SAP. Below you will find an email which was sent and responded to by IBM and Novell on these topics...

"As you may know, Home Depot has embarked on an IBM led proof of concept using SUSE SLES10 running in zVM guests on IBM zSeries hardware to host SAP server instances. The Home Depot IT organization is currently in the midst of a large scale push to modernize our merchandising and people systems on SAP platforms. The zVM/SUSE/SAP POC is part of that effort, as is a parallel POC of an Intel Blade/Red Hat/SAP platform. For our production financial systems we now use a pSeries/AIX/SAP platform.

So far in the zVM/SUSE/SAP POC, we have been able to create four zVM LPARS on IBM z9 hardware, create twelve zVM guests on those LPARS, boot SLES10 in those guests, install and run SAP instances in those guests using hipersockets for access to our DB2 SAP databases running on zOS, and direct user workloads to the SAP instances with good results. We have also successfully developed cloning scripts that have made it possible to create new SLES10 instances, configured and ready for SAP installs, in about 10 seconds using FLASHCOPY and IBM DASD.

I am writing in the hope that you can direct us to technical resources at IBM/Novell/SAP who may be able to field a few questions that have arisen. In our discussions about optimization of the zVM/SUSE/SAP platform, we wondered if any wisdom about the appropriateness of and support for using zVM capabilities to virtualize SAP has ever been developed or any best practices drafted. Attached you will find an IBM Redbook and a PowerPoint presentation which describes the use of the zVM discontiguous shared segments and the zVM named saved system features for the sharing of reentrant code and other elements of Linux and its applications, thereby conserving storage and disk resources allocated to guest machines. The specific question of the hour is, can any SAP code be handled similarly? Have specific SAP elements eligible for this treatment been identified?

I've searched the SUSE Knowledgebase for articles on this topic to no avail. Any similar techniques that might help us reduce the total cost of ownership of a zVM/SUSE/SAP platform as we compare it to Intel Blade/Red Hat/SAP and pSeries/AIX/SAP platforms are of great interest as we approach the end of our POC. Can you help?

Greg McKelvey is a Client I/T Architect at IBM. He found the attached IBM documents and could give a fuller account of our POC. Pat Downs, IBM zSeries IT Architect, has also worked to guide our POC. Akshay Rao, IBM Systems IT Specialist - Linux | Virtualization | SOA, is acting as project manager for the POC. Jim Hawkins is the Home Depot Architect directing the POC. I've CC:ed their email addresses. I am sure they would be pleased to hear from you if there are the likely questions about what the heck I am asking about here. And while writing, I thought of yet another question that I hoping somebody at SAP might weigh in on; are there any performance or operational benefits to using Linux LVM to apportion disk to filesystems vs. using zVM to create appropriately sized minidisks for filesystems without LVM getting involved?"

As you can see, implementation questions need to be resolved. We have heard from Novell that the SLES10 Kernel and other SUSE artifacts can reside in memory and be shared by multiple operating system images. Does SAP support this configuration? Also, has SAP identified SAP components which are eligible for similar treatment? We would like to make sure that any decisions we make about the SAP platforms we are building will be supportable. Any help you can provide will be greatly appreciated. I will supply the documents referenced above if they are not known to any answerer. Thanks, Al Brasher 770-433-8211 x11895 al_brasher@homedepot.com