SeparatingApplication Server from Central Services

[s0007045141]

Hi gurus, we need to move our application servers from AIX to Linux and we have NW 7.11, right now our Central Services are in the same instance and server than the first application server, and we need to separate them.

I think we can install another application server point it to existing central servicies and everything will work ok, but I can not figure it out how I can switch off the original application server that is with central services.

I don't know if I can comment start profile line related to dw process and that's all or there is something I'm missing.

Does anybody face this situation before, what do you think?

regards

[s0007045141 · Accepted solution]

Dear Effan, we agreed that for PRD where we have a distributed installation and we won't have any problem.

For QAS ad DEV where we have CI (ASCS+DI); we can install additional application servers on Linux.

After we install those application servers, we need to deinstall our original application server on AIX. This appl srv is part of the CI (same system number for ASCS and DI). So we can not deinstall ir, ok?

So, if we can not deinstall appl server, maybe we can avoid to start it up just commenting this section in startup profile

#----

---

1. Start application server

#----

---

DW = dw.sap$(SAPSYSTEMNAME)$(INSTANCE_NAME)

Execute_09 = local rm -f $(_DW)

Execute_10 = local ln -s -f $(DIR_EXECUTABLE)/disp+work$(FT_EXE) $(_DW)

Start_Program_02 = local $(_DW) pf=$(_PF)

this will avoid to launch disp+work process.

Am I right?

[Former Member · Accepted solution]

I see your point, but you cannot do it this way. This central instance plays the role of first "application server", which needs to have at least 2 dialog work processes to run a bunch of reports when system is being started. It's mandatory and ideal quantity of dialog work process should be the sum of all other work processes as a rule of thumb, regardless of application program workload. The "application servers" in my previous replies, which refers to the 2nd or more application servers you're going to add, that's why it's called "additional".

In your own environment, you could try minimize the quantity of dialog process by 1-2 each time to see how it runs without affecting performance. But like I explained, it should be in the range of 2 to sum of all other processes on CI.

Regards,

Effan

[s0007045141]

OK; I finally get it. Primary application server can not be deinstall in our installation. We can minimize it o take it off from SMLG but it will always run.

Thnaks a lot for all your help.

[brian_walker]

Gustavo,

First, hello again! I hope your migration from DB2 LUW on AIX to DB2 z/OS and Linux application servers is going well. I think what you are wanting to do in this case is to use sapinst to perform a system copy. This is the only supported way to move the CI. We encountered exactly the same issue when we moved from zLinux to Windows application servers, even for distributed/HA systems. It was easy to just install another DI on Windows (instead of Linux) and that worked great. To actually move the CI, you have to do a system copy (homogeneous since the DB will not change or need to be exported).

Brian

[s0007045141]

This is a 7.11 installation, in PRD we have all components distributed in HA. So we have 1 host with ASCS, 1 host with DB, 1 host with ERS, 1 host with Web Dispatchers and 2 hosts with application servers. So in that installation we won't have any problem moving our application servers from AIX to Linux.

On QAS, we have 1 host with CI (ASCS+ApplSrv), 1 host with DB, 1 host with Web Dispatchers and 2 hosts with additional application servers. In that case we can move our application servers from AIX to Linux, but we can not deinstall our primary application server because it is installed in the same host with ASCS, and they have same System Number, right? in that case, can I modify mi startup profile in order DW process won't start?

We don't have any performance situation wich lead us to install several applicatio servers in QAS, it was just a desition taked in order to have the same landscape as we have in PRD, because we have a lot of interfaces connected against message server.

regards

[Former Member]

> In that case we can move our application servers from AIX to Linux, but we can not deinstall our primary application server because it is installed in the same host with ASCS, and they have same System Number, right?

In distributed installation, you need at least one application server since it's not an all in one central system.

>in that case, can I modify mi startup profile in order DW process won't start?

I don't quite follow, please elaborate for me.

[s0007045141]

Right now, I see only 1 instance on SM51 for DEV environment.

In QAS / PRD I have 2 instance in SM51

Regards

[Former Member]

> In QAS / PRD I have 2 instance in SM51

That's the answer I concerned. So you do have an additional application server installed in PRD, and I think it's installed on the same host with CI?

Back to your question, you could install another DI on Linux and then deinstall the one installed on CI host. Please do make sure that the instance you are about to uninstall is the application server which has a different system number than CI.

BTW, why do you have DI for QAS? Is there a great performance issue which is rarely to see in QAS?

Regards,

Effan

[s0007045141]

Hi Effan, thanks for your answer.

If I understand your answer, I could install several additional application servers on Linux and, after that, I could deinstall primary application servers from my CI, am I right?

I know that we can take off application servers from SMLG; but we don't want to start anymore DW process on AIX.

Regards

[Former Member]

> I could deinstall primary application servers from my CI, am I right?

Hold on to it, that takes us back to my initial question, how many instances you can see in SM51 now?

[Former Member]

Hello my friend

Help me understand your architecture clearly, how many instances in this <SID> right now, 1 or 2 in SM51?

It sounds like you have 2 instances, 1 CI+DB and 1 DI. If so, it's safe to uninstall the DI on AIX and go ahead install a new one on linux host. Not a problem at all.

If it's just 1 instance, which means this is a 2 tier architecture and CI plays the application server role as well, you still could go install the new DI on linux host. To separate CI completely from application server level, after finishing adding the new DI into this <SID>, go to SMLG and then remove CI instance from the logon group, then workload of user logon and application program calculation will not be dispatched to CI any more.

Regards,

Effan