SAP System Performance Issues

My server becomes slow when more users login.
What could be the reason?  Is it because of less hardware resource?

Server configuration is 104GB HDD, 2GB Ram.
OS:Win 2003 server.
Database:Oracle.

I manage SAP R/3 4.6C systems on Risc 6000 machines, under Oracle 9.2.

The overall performance problem for me is to know if SAP response time is acceptable ; if not, do this :
- at AIX level : utilities are topas, to catch what's wrong : Disk I/O ? CPU bottleneck ? Too much swap ?
- at Oracle level : tkprof but don't know much about this.
- at SAP level : you can manage SAP memory, Oracle and OS too.

If SAP response time is acceptable, then try this :

Try to have a look at OS response time : ST06 : look at CPU, Memory, Swap, Disk and Lan response time.

Try to have a look at buffer quality : ST02, if many fields are red, investigate each fields dependant parameters.

Try to have a look at DB response time : ST04N, databuffer quality (SGA zone), how much physical reads / logical reads Ratio, wait times, number of user calls, Shared Pool cache hit ratio should be >96%, Sort usage, Redo logging.

I use this kind of procedure to manage my systems.

It depends how much you allocated for SGA (database buffers, shared pool buffer, redo log buffers), how much you allocated for SAP buffers esp. Program buffers and whether the server have any other external processes/programs running.

How many Dialog Work Processes you allocated…I think your problem most likely is you don't have enough of these Dialog processes. Also maybe users running inefficient reports/programs which are holding the Dialog processes, goto SM50 & check all DIA (Dialog) with status "waiting"…if ALL are "running" then you have wait time (problems !) for other users wanting to process transactions .

To troubleshoot performance, you need these tcode tools:-

ST04 – Database  ß in here, check especially for Expensive SQLs (Detail Analysis à SQL Request)

ST02 – SAP buffers

ST06 – OS stats

ST05 – SQL trace

SE30 – Abap runtime analysis

A few step which you can exercise to sort/identify performance issues.

* ST03, ST02, ST04 are the tcode for workload, tuning and DB Performance Monitoring codes.

* ST06 FOR Operation System Monitoring.

** SM51 OR SM50 is process overview which tells you the workprocess sequence. ( Ideally 10-15 process with  OLTP and batch process scheduled at peak and off peak times respectively) say 8-17 hrs and 17-8 hrs for Batch Process)

Operation Mode can be configured in RZ04 tcode.

** Check for top CPU in ST06 tcode.  CPU should not exceed more than 60% for long time for any process.

** Based of No. of instances ( Application Servers ) should have adequately sized.

** Most resources intensive process have to be scheduled in Batch Process ( in Background in Non Peak Hours )

** Look for unnecessary Jobs Active During Prime  Time
** Look for Parameters Set To Your Business Process.
   ( RZ10, RZ11 ) Check Snote:0124361

** Refer Early Watch Alert Periodically for Overall System Performance.. ( Tcode SDCC )