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Rule of thumb for configuring work processes/ RFC handling

Former Member

Dear experts,

we're running an EWM test system and prepare for go-live. We have18 communication points that send and receive (JCo based) data to/from EWM via RFC. In addition we have around 50 concurrent users (forget this for the moment).

I wonder about the following:

    1. How many workprocesses can an application server handle before we should create another instance? The test system is a 64GB, 8 CPU, 8000 SAPS server, the production system a 384GB, 16 CPU, 48000 SAP server. Can I configure it for 120 DIA, 8 UPD, 2 UP2, 5 BTC, 2 SPO? Background: We don't have significant batch jobs running (never see more than two active) and all communication is RFC based with >40 calls coming in per 100ms at peak.
    2. We see delays in RFC handling. Trx. SAT shows sometime 10secs or more:

      A wireshark trace however indicates that it's the SAP Server who doesn't respond for 10 secs. I wonder if something in the gateway must be configured or checked? We are not clear where the time is consumed. The same call would normally take 300ms (not 10secs).

I would appreciate some ideas from the experts here. We are on Netweaver 7.4 SP11.

Kind regards,

Gunter

Accepted Solutions (1)

Accepted Solutions (1)

isaias_freitas
Advisor
Advisor

Hello Gunter,

To ensure optimal performance of the Gateway, read the SAP note 384971.

In addition to the parameters mentioned on that note, set "gw/max_overflow_usage = 80".

Do not set the parameters "rdisp/appc_ca_blk_no" and "rdisp/wp_ca_blk_no".

Since your system is based on NW7.4, the SAP kernel will calculate the appropriate values at startup, automatically.

If SAP runs on Linux/UNIX, ensure that the "nofile(descriptors)" limit, at OS level, are set to a high enough value.

About the maximum number of work processes per instance, for NW74 it is 512 (SAP note 9942).

You might also want to read the SAP note 74141 to ensure that the RFC processing parameters are correctly set for your needs.

Kind regards,

Isaías

Former Member
0 Kudos

Very helpful answer Isaías,

will do so. I found an interesting info of SAP related to Netweaver AS on Windows (and we run it on Windows): Determining the Number of Work Processes - Memory Management (BC-CST-MM) - SAP Library

Taking that into account would mean on a 16 CPU Core machine we can only configure 16 * 5 = 80 WPs? Which means like 70 DIA because ~10 we would need to distribute to the other WPs. Is my understanding correct?

Oh and the info of "blockade handling" in SM50: Does this mean we have a bottleneck for the WPs?

Regards,

Gunter

isaias_freitas
Advisor
Advisor
0 Kudos

Hello Gunter,

Your calculation is correct.

According to that SAP Help page you mentioned, 80 WPs would be a good number.

The "blockade handling" is related to the "dynamic work process" feature of the SAP kernel.

When all work processes of a certain type are busy (let's say all your 4 UPD processes are busy), and the Dispatcher receives another request of that type (UPD, in this example), the Dispatcher can create a dynamic, temporary work process.

If the "blockade handling" number increases too much in a short period, it would be good to consider increasing the number of work processes of the affected type.

This WIKI page has information about the dynamic WPs.

Dynamic work processes configuration - Application Server Infrastructure - SCN Wiki

Kind regards,

Isaías

Answers (0)