4 Replies Latest reply: Dec 5, 2008 5:20 PM by David Hurst RSS

Mixed application server environment with z/OS

David Hurst
Currently Being Moderated

Hello,

 

I'm looking for more information from SAP when running a system in a mixed application server platform environment.   In other words, the system would look like the following:

 

1.  Central instance (only MS and EN processes -  i.e. standalone enqueue) running on AIX

2.  Dialog instance (disp+work processes - i.e. spool, batch, dialog, upd) running on Windows 2003 or Linux

3.  Database running on z/OS

 

I see from the Product Available Matrix, that Windows and/or Linux are supported with z/OS, but there is no mention of running a mixed environment as described above.

 

Any help/guidance would be appreciated.

 

Regards,

David

  • Re: Mixed application server environment with z/OS
    Brian Walker
    Currently Being Moderated

    Hi David!

     

    If you're going to commit to running DB2 for z/OS, have you considered running the ASCS/SCS under USS for z/OS? This is the recommended approach for HA when using zSeries. If you decide to, this is what we have done and I could offer some advice/help.

     

    From my experience, if you did want to run ASCS/SCS standalone on AIX, the easiest thing to do would be having your application servers also on a unix platform (AIX, Linux, etc) rather than Windows. This is because the directory structure for the SAPMNT share is handled slightly different between unix and Windows (Windows doesn't understand symbolic links). Generally speaking you have SAPMNT shared from the ASCS/SCS system. The one place that breaks down is USS for z/OS because the NFS server under z/OS (at least 1.8) performs 4x or more slower than other NFS implementations, even on the same hardware. Although SAP "supports" mixed unix and Windows environments, having lived through that I wouldn't recommend it if you like having hair.

     

    Your other option would be to install ASCS/SCS on Windows and the application server also on Windows. If you went that route, then unless you've already got sunk cost in a zSeries server or you require more database horsepower than is currently available with the maximum number of x64 cores available in a server or you have some extremely rigid downtime requirements that require DB2 datasharing, I'd recommend using SQLServer for the database and going 100% Wintel.

     

    Brian

  • Re: Mixed application server environment with z/OS
    Marco Mica
    Currently Being Moderated

    Brian,

       We are also running windows / zDB2 with the ASCS/SCS on USS. Have you also tried running a mix of windows and zLinux app. servers in this setup ? zLinux seems to have some features which could be useful when importing/loading large volumes of data.

    Were you seeing inconsistencies between win and Unix or also win and Linux ?

    • Re: Mixed application server environment with z/OS
      Brian Walker
      Currently Being Moderated

      Yes, we have already been down the road of zLinux. Thanks to some pricing issues on the DB2 z/OS side, we had to give up our IFLs and thus zLinux. Our application servers are now on Windows 2003 x64. Even when we were on zLinux, we were forced to run some Windows application servers for Adobe Document Services as this is not supported on zLinux and SAP/Adobe have thus far refused to port it.

       

      The inconsistency is that while SAP says it is "ok" to use something like SAMBA to share out SAPMNT and have it work under windows, it introduces unneeded complexity in many areas. SAP note 680617 describes this process. For us, it was a neverending headache with the unix vs windows text file format differences (supposedly handled by instance parameter abap/NTfmode=b) and there are complications for path names for batch jobs, etc.

       

      I am sure all of those issues can be sorted out eventually, but it is just much easier to stick with one application server platform.

       

      If you're considering zLinux, I would be extremely careful. There are only a handful of SAP customers in the world running it. Most likely you'll run into problems that no other customer has encountered yet and which will require a PTF or a new SAP kernel to fix (when you can finally get them). We ran into one such problem communicating to the ASCS/SCS in USS from zLinux over hipersockets. This really plagued our project team with hung locks (especially during LSMW imports of master data) until SAP released kernel 150 for zLinux which coded around the "unexpected" extreme low latency of hipersockets.

       

      Caveat emptor.

       

      Brian

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