How to estimate application servers number

[Former Member]

Dear all,

I have a question about system sizing: how to estimate how many application servers we need in a system landscape? I can't find any information from SAP sizing.

For example, we have 5,000 end users, then how many application servers we need install? Is this estimation based on expierence or there have tools or documents?

Thanks

Michael Wang

[Former Member · Accepted solution]

Hi Michael,

Sizing of application servers depends on different scenario, SAP Version, DB, OS, How many active users and there activities, common background jobs, month end activities, users locations other activities. I Guess 12-15 Application servers you required.

This link may help you in detail.

http://service.sap.com/sizing

Reward points if helpful.

Regards,

Ganesh

[sascha_tubbesing · Accepted solution]

wow.

wait a minute.

12-15 application servers?

We are not talking about java server processes here. At least I thought so.

There are systems with one single ABAP Instance (application server) and 5000 users working on it.

Regards,

Sascha

[Former Member · Accepted solution]

hi both two,

Thanks for your answer.

I agree that the application servers' number depend on the business requirements, active end users, and so on. But how did you get the number, 1 or 10? Just guess?

I think SAP should have a method to estimate it.

BTW, Ganesh, I still couldn't find any information about applicaiton server in http://service.sap.com/sizing or http://servive.sap.com/quicksizing. Maybe I entered wrong path. please give me the detail path if you conveniently.

Thanks

Michael

[Satyabrata_Basu · Accepted solution]

Hi Michael,

you have to base the sizing on Number of Concurrent users at peak time and not on total number of named user. Do you expect all 5000 of your users to logon at the same time ?

You have to see how many workprocess per application server you are configuring. Also, your platform. for example if you have 64-bit platform you can assign almost peta-bytes level of memory but it's not possible for 32-bit system (or in Windows). Then you have some limit on configuring too many workprocess in one server and you then will need to go for more application servers.

So, the things you need to consider:

1. Your platform (Unix, AS/400, Windows, 32-bit, 64-bit)

2. H/W resource (how much RAM, CPU power etc)

3. Number of concurrent users

4. Batch jobs/external Interface load

5. high Availability, Logon loadbalancing etc

Hope this helps....

Cheers !!

Satya.

PS: Pls reward points if the answer was helpful...thx.

[Former Member · Accepted solution]

Hi Satya,

Thanks for your reply. It's very helpful

Another question: Based on your expierence or SAP standard (if they have), how many concurrent users can working on one dialog work process? for example, in this case we have 1000 concurrent users at peak time, how many dialog work processes we need configure?

Thanks

Michael

[Satyabrata_Basu · Accepted solution]

Hi Michael,

from my experience I generally configure 1 DIA workprocess per 4 (until 5) online users. So, if you have 1000 concurent user at the peak time, roughly around 200 DIA workprocess would be okay...

Cheers !!

Satya.

[Former Member · Accepted solution]

Hi Satya,

Thanks very much! Then I can estimate how many instance we need.

Good day!

Michael

[sascha_tubbesing · Accepted solution]

Hi again,

if you have 1000 concurrent users. The numbers of workprocesses you need depends on the response time you want to have and on how long an average dialog request takes.

Let assume one click (one dialog request) in the system takes about 0.1 seconds processing time for the dialog wp (this time strongly depends on what you are doing of course).

As one dialog wp can only work on one request at the same time, he will take 1 second to answer 10 requests. So you can have an average response time of one second for 10 users and 1 DIA wp. In this case you will need to have 100 DIA wps for 1000 users to have an average response time of one second.

Regards,

Sascha

[Satyabrata_Basu · Accepted solution]

Hi Michael,

you are vey much welcome.

And all the best with your project

Cheers !!

Satya.

[sascha_tubbesing]

Hi,

I don't know any official document talking about some calculation of the number of instances.

Also 5000 end users can have very different memory requirements depending on the application the are using.

Maybe note https://service.sap.com/sap/support/notes/9942 is a bit helpful.

It mainly talks about the maximum number of wps.

Regards,

Sascha