Confusion over number of running VUsers in LR vs. the actual number of active user reported in SAP
Dear LR Experts,
I have a performance target of SAP system to test against. I need to have 2,400 concurrent SAP users doing work in MM, FI, PM following our load profile.
On the SAP side, we have 1 x CI, 1 x Oracle DB Server and 3 x App Servers. (all HP-UX)
- SAP Architect told us this SAP system could take up to 6000 users.
- SAP ECC6
On the LR side, we have:
- LR Controller (v. 11.52) running on a PC Core i3 with RAM 4GB - LR Load Generators (v. 11.52) running on 20 boxes of DL 380 G5 with 24 GB RAM each. - each of these DL boxes has Windows 2008 server R2 SP1 on it. - I launch 2 terminal sessions for each Windows 2008. Then I assign 70 VUsers to each session. - So, I can do 2 x 70 = 140 Vusers for a DL box. For 20 boxes, I have 140 x 20 = 2,800 Vusers in total.
- Btw, SAPGUI 7.30 Patch 4
Here comes the trouble:
We start to ramp up Vusers at a rate of 1 per 3 seconds. Everything looks ok until the #Vusers start to reach 800. New Vusers can’t easily log on. CPUs on all app servers are peaking. Memory is left thin. Dialog step response time is horrible. SAPGui are timing out left and right.
The SAP team keeps tuning parameters: #work processes, memory allocation, etc, etc..
We eventually give all CPU resources, memory out to those 3 app servers. Each app server get 48GB RAM with 10 CPU cores. Nothing to give more – but only to be able to take in a hundred Vusers more. This is far from the target of 2,400 Vusers.
We decide to do simple logon test where we do nothing at all in the Action part of the LR script. We just do SAP login in the init. Then, stay idle for about an hour (using lr_think_time) and then leave. Here is what we found..
Test_1) we schedule LR to do 10 VUsers logging on to SAP. But when we run tcode AL08 on a separate GUI session, we see SAP reporting 40 active users.
Test_2) we do 100 VUsers. SAP says 210 active users in AL08.
Test_3) we do 500 VUsers. SAP says 949 active users in AL08.
Test_4) we do 1000 VUsers. SAP says 3654 active users in AL08.
Test_5) we do 3000 Vusers. SAP says 6154 active users in AL08.
Now our SAP Basis Team becomes suspicious about LR behavior.
Which is correct?
Number of Vusers commanded by LR or Number of active users reported in AL08??
Most critical is that the existing SAP production system is already serving 1,200 users. But our new system (with super duper hardware) is just handling 800+ users (through LR, but, as I said SAP tcode-AL08 reported something different ; it showed 3xxx active users).
I just can’t convince customer to not look at the LR Controller screen, not observing the #running VUsers graph and just pay attention to what being reported on AL08.
Re: Confusion over number of running VUsers in LR vs. the actual number of active user reported in S
I am not sure if this has anything to do with it...
1.) For the sake of convenience, I use only one SAP user id (with multiple log on enabled) to generate those concurrent sessions.
2.) Each of VUser does only 1 login in the Init step. Once the user gets into the Action part, it keeps doing MM/FI/PM activities repeatedly. Until the test runs for about 2 hours, then VUser goes into the End part and log off. (i.e. what I am trying to explain here is that I didn't accidentally launch any extra SAPGui session -- 1 session for 1 Vuser only.