week 3: icm and sap web dispatcher services unit …...the web admin page documentation references...

Week 3: ICM and SAP Web Dispatcher Services

Unit 1: Introduction

2PUBLIC© 2017 SAP SE or an SAP affiliate company. All rights reserved. ǀ

IntroductionICM and SAP Web Dispatcher

ICM stands for “Internet Communication Manager”.

Each instance has its own, local ICM process.

The ICM handles HTTP, HTTPS, and SMTP

communication, besides other protocols used at an

SAP NetWeaver Application Server Java (telnet, P4,

IIOP).

The ICM can act as the server or as a client.

The SAP Web Dispatcher is a load balancer. It

handles HTTP and HTTPS communication only.


IntroductionICM architecture (1)

Multithreaded

– mpi/buffer_size: defines the size of each MPI buffer

/ block

– mpi/total_size_MB: defines the size of the MPI

memory area

– mpi/max_pipes: defines how many pipes (event-

flags, semaphores) are available to the ICM


IntroductionICM architecture (2)

ICM

Client

ICMABAP work

process

If no work process is available, the ICM stores the request in the MPI memory

area.

A single request cannot use the entire MPI memory (protection mechanism).

Client

ICMABAP work

process

ClientABAP work

process

direct stream

waits

waitswaits

The request data is streamed to the work process.


Timeout settings per service, defined at the parameter “icm/server_port_X”

icm/server_port_X = PORT=…, PROT=…, TIMEOUT=60, PROCTIMEOUT=600

TCP/IP connection idle timeout

– TIMEOUT argument when acting as the server

– Parameter “icm/HTTP/client/keep_alive_timeout” when acting as the client

Processing timeout (PROCTIMEOUT)

Timeout for establishing new outgoing connections (icm/conn_timeout)

Session idle timeout (HTTP → rdisp/plugin_auto_logout; ITS → rdisp/gui_auto_logout)

HTTP security session timeout (http/security_session_timeout)

IntroductionRequest timeouts (1)

Client ICM ABAP work processTIMEOUT PROCTIMEOUT

ICM Remote HTTP serverPROCTIMEOUT

ICM as the

server

ICM as the

client icm/HTTP/client/keep_alive_timeout


SAP Note 824554: ICM and SAP Web Dispatcher

timeout parameters

Example of “500 timeout” raised by

“PROCTIMEOUT”:

Example of “400 timeout” raised by

“rdisp/plugin_auto_logout” or

“http/security_session_timeout”:

IntroductionRequest timeouts (2)

https://launchpad.support.sap.com/#/notes/824554

Contact information:

[email protected]

Thank you.

No part of this publication may be reproduced or transmitted in any form or for any purpose without the express permission of SAP SE or an SAP affiliate company.

The information contained herein may be changed without prior notice. Some software products marketed by SAP SE and its distributors contain proprietary software components

of other software vendors. National product specifications may vary.

These materials are provided by SAP SE or an SAP affiliate company for informational purposes only, without representation or warranty of any kind, and SAP or its affiliated

companies shall not be liable for errors or omissions with respect to the materials. The only warranties for SAP or SAP affiliate company products and services are those that are

set forth in the express warranty statements accompanying such products and services, if any. Nothing herein should be construed as constituting an additional warranty.

In particular, SAP SE or its affiliated companies have no obligation to pursue any course of business outlined in this document or any related presentation, or to develop or release

any functionality mentioned therein. This document, or any related presentation, and SAP SE’s or its affiliated companies’ strategy and possible future developments, products,

and/or platform directions and functionality are all subject to change and may be changed by SAP SE or its affiliated companies at any time for any reason without notice. The

information in this document is not a commitment, promise, or legal obligation to deliver any material, code, or functionality. All forward-looking statements are subject to various

risks and uncertainties that could cause actual results to differ materially from expectations. Readers are cautioned not to place undue reliance on these forward-looking statements,

and they should not be relied upon in making purchasing decisions.

SAP and other SAP products and services mentioned herein as well as their respective logos are trademarks or registered trademarks of SAP SE (or an SAP affiliate company)

in Germany and other countries. All other product and service names mentioned are the trademarks of their respective companies.

See http://global.sap.com/corporate-en/legal/copyright/index.epx for additional trademark information and notices.

© 2017 SAP SE or an SAP affiliate company. All rights reserved.

http://global.sap.com/corporate-en/legal/copyright/index.epx


Unit 2: The Web Admin Page


“/sap/admin” for the ICM, “/sap/wdisp/admin” for the SAP Web Dispatcher

The Web Admin PageAccessing the Web Administration page


Internet Communication Manager (ICM) - SAP NetWeaver

Managing PSE files at the Web Dispatcher (WIKI page)

SAP Note 1026191: Limitations on the HTTP router protocol in Web Dispatcher

Web Dispatcher as a URL filter

SAP KBA 2078179: Issues with CRM, SRM, etc via Web Dispatcher when using logon groups

Managing user IDs for the Web Administration Page (WIKI page)

SAP Note 2390858: ICM - Web Dispatcher: Whitelist for OS user authentication

The Web Admin PageDocumentation references

https://help.sap.com/doc/saphelp_nw74/7.4.16/en-US/5a/915311b729421089f7706f9ee6771e/frameset.htm

http://wiki.scn.sap.com/wiki/x/tIahG


http://wiki.scn.sap.com/wiki/x/iBZQGg


http://wiki.scn.sap.com/wiki/x/0wliGQ



[email protected]

Thank you.


Unit 3: Tuning the ICM/SAP Web Dispatcher

for High Load


ICM and SAP Web Dispatcher

– icm/max_conn: maximum number of concurrent

open connections

– icm/req_queue_len: maximum number of requests

waiting for processing

– icm/min_threads: minimum number of worker

threads

– icm/max_threads: maximum number of worker

threads

– mpi/total_size_MB: size of the MPI memory area

– mpi/max_pipes: maximum number of memory pipes

(event-flags, semaphores) available

– mpi/buffer_size: size of each MPI buffer/block

Tuning the ICM/SAP Web Dispatcher for High LoadParameters (1)


SAP Web Dispatcher only:

– wdisp/HTTP/max_pooled_con: maximum number of HTTP connections to each back-end server

– wdisp/HTTPS/max_pooled_con: maximum number of HTTPS connections to each back-end server


Clients Web Disp.

Instance 00

Instance 01

wdisp/HTTP(S)/

max_

pooled_

con


Default values:

– icm/max_conn = 2000 for ICM / chosen at

installation time for the SAP Web Dispatcher (2000

is the default suggestion)

– icm/req_queue_len = 6000

– icm/min_threads = 10

– icm/max_threads = 500

– mpi/total_size_MB = 6% of icm/max_conn + 50;

maximum of 2000 (megabytes)

– mpi/max_pipes = 2x icm/max_conn

– mpi/buffer_size = 65536 (bytes; 64KB)

– wdisp/HTTP/max_pooled_con = icm/max_conn

– wdisp/HTTPS/max_pooled_con = icm/max_conn

Tuning for high load: change “icm/max_conn” and

“icm/min_threads” only



*** WARNING => IcmReadFromConn(id=3/118): temporarily out of MPI buffers -> roll out

[icxxthrio.c 3223]

– A single connection sending a large request or too many connections in parallel?

– Free dialog work processes?

*** ERROR => no more free event-flags. [mpixx.c 6070]

MpiEvtOpen -1 -1 -> MPI_EEVT: Event flag error

*** ERROR => MpiIEvtOpen(0) failed: 11 [mpixx.c 1793]

MPI:3999 create pipe c0000000e02039d0 0

*** ERROR => IcmConnInitBuffer: MpiCreate2 failed (rc=MPI_EEVT: Event flag error/11)

[icxxconn.c 4957]

– “mpi/max_pipes” is not high enough.

Tuning the ICM/SAP Web Dispatcher for High LoadHigh load situations (1)


*** WARNING => IcmAcceptClient: server overload: conn: 500 - accept delayed [icxxman.c 5290]

– Increase “icm/max_conn”.

[Thr 139780162316160] *** ERROR => IcmAcceptClient: NiAccept from <client IP address> failed

with NI error -8 (NIEINVAL) [icxxman.c 5386]

[Thr 139780162316160] *** ERROR => NiIAccept: SiAccept failed for hdl 33/sock 11

(SI_EMFILE/24; I4; ST; own high 499; max hds 2000) [nixxi.cpp 3607]

– Operating system limit “open files” / “nofiles” / “descriptors” has been reached.

SAP Note 2007212: Tuning SAP Web Dispatcher and ICM for high load

Tuning the ICM / SAP Web Dispatcher for high loadHigh load situations (2)



[email protected]

Thank you.


Unit 4: SAP Web Dispatcher for Multiple Systems


Parameter “wdisp/system_<index>”

– SID = <backend System ID>

– MSHOST = <hostname of Message Server>

– MSPORT = <HTTP port of Message Server>

or

– MSSPORT = <HTTPS port of Message Server>

– <argument(s) for selection criteria>

– Parameter “wdisp/system_conflict_resolution”

– Web Dispatcher for Multiple Systems WIKI

SAP Web Dispatcher for Multiple SystemsConfiguring the systems

http://wiki.scn.sap.com/wiki/x/m4D3GQ


SRCURL

– wdisp/system_0 = SID=ECC, …, SRCURL=/sap;/nwbc

– wdisp/system_1 = SID=EPP, …, SRCURL=/

SAP Web Dispatcher for Multiple SystemsSelection criteria (1)

User accesses:

/sap/bc/gui/sap/its/webgui

SAP Web

Dispatcher

System

EPP

User accesses:

/irj/portal

System

ECC


User accesses

through port 8080

SAP Web

Dispatcher

System

EPPUser accesses

through port 80

System

ECC

SRCSRV

– icm/server_port_0 = …, PORT=80, …


Using the port:

– wdisp/system_0 = SID=ECC, …, SRCSRV=*:8080

– wdisp/system_1 = SID=EPP, …, SRCSRV=*:80



SRCSRV



Using the (physical!) host:

– wdisp/system_0 = SID=ECC, …, SRCSRV=ecc.company.com:*

– wdisp/system_1 = SID=EPP, …, SRCSRV=ep.company.com:*


User accesses

through host “ecc...”

SAP Web

Dispatcher

System

EPPUser accesses

through host “ep...”

System

ECC


SRCSRV



Using both:

– wdisp/system_0 = SID=ECC, …, SRCSRV=ecc.company.com:8080

– wdisp/system_1 = SID=EPP, …, SRCSRV=ep.company.com:80


User accesses

through host “ecc...”

and port 80

SAP Web

Dispatcher

System

EPP

System

ECC

X


SRCVHOST

– Works in the same way as SRCSRV

– Uses the HTTP header “host”

– No DNS lookup performed (DNS alias can be used)

– wdisp/system_0 = SID=ECC, …,

SRCVHOST=ecc.mycompany.com:8080

– wdisp/system_1 = SID=ECC, …, SRCVHOST=ep.mycompany.com:80


User accesses

through DNS alias “ecc...”

and port 8080

SAP Web

Dispatcher

System

EPP

System

ECC


[email protected]

Thank you.


Unit 5: Load Balancing with the SAP Web Dispatcher


Stateless:

Each request is independent of previous requests.

Each request can be load-balanced.

Stateful:

A request can depend on information from previous

requests (application state).

Only the first stateful request must be load-balanced.

Load Balancing with the SAP Web DispatcherIntroduction: stateless vs. stateful

Clie

nt

Request 1

Serv

er

Temporary data for

request 1

Response 1Temporary data for

request 1XRequest 2

Temporary data for

request 2

Clie

nt

Session 1 Request 1

Serv

er

Data for session 1Response 1

Session 1 Request 2

Response 2


Message server load

balances with HTTP

redirects. Client must

be able to access all

instances directly.

Only one load balance

algorithm is available.

Not supported for

stateful applications.

Bookmarked pages will

bypass the load

balancing mechanism.

Load Balancing with the SAP Web DispatcherIntroduction: load balance through the message server


Configured with the parameter

“wdisp/load_balancing_strategy”.

Possible values:

– simple_weighted_round_robin

– weighted_round_robin (default)

– adaptive

Load Balancing with the SAP Web DispatcherLoad balance algorithms (1)

Clients Web Disp.

Instance 00

Instance 01

wdisp/load_

balancing_

strategy = ?


simple_weighted_round_robin

A server with “k” capacity receives “k” requests before

the next server takes over.

Capacity = number of dialog work processes


Clients Web Disp.

Instance 00

DIA = 40

Instance 01

DIA = 20


weighted_round_robin

Uses a “load factor” (estimation of the current load).

Instance with the lowest “load factor” receives the next

request.

Requests pending for the instances are also taken into

account.

“Load factor” is calculated per instance.


Load on

instance 00

Load on

instance 01

0 0

Request1 0 -> 400 0

Request2 400 0 -> 800

Response1 400 -> 0 800

Request3 0 -> 400 800

Request4 400 -> 800 800

Response2 800 800 -> 0

Instance 00DIA = 40

Calculated load factor = 400

Instance 01DIA = 20

Calculated load factor = 800


adaptive

Works in the same way as the “weighted_round_robin” algorithm.

Difference: “load factor” dynamically calculated based on the “ping” response time.



HTTP / HTTPS

– Session cookies

– Session ID

ROUTER

– IP address of the client

– Parameter

“wdisp/HTTPS/sticky_mask”

Load Balancing with the SAP Web DispatcherSession persistence

HTTP header:

cookie: sap-contextid=SID%3aANON%3aeccbrasil_PLR_30%3apE2WgyjLq4kyI

YAOyYkI6c-sl5V3hAjcpeCAAjKH-ATT

URI parameter

http://webdispatcher/sap(bD1kZSZjPTAwMA==)/bc/bsp/sap/it00/basic_abap.htm


Load balance values are reset at every two minutes (“wdisp/lb/auto_reset=1” by default; “wdisp/auto_refresh

= 120” by default).

Number of logged on users, memory, and CPU power are not considered (directly) by any of the load

balance algorithms.

Number of HTTP sessions is not a good indicator of the load balance distribution.

Load Balancing with the SAP Web DispatcherFinal considerations


[email protected]

Thank you.




SAP and other SAP products and services mentioned herein as well as their respective logos are trademarks or registered trademarks of SAP SE (or an SAP affiliate

company) in Germany and other countries. Please see http://global12.sap.com/corporate-en/legal/copyright/index.epx for additional trademark information and notices.

Some software products marketed by SAP SE and its distributors contain proprietary software components of other software vendors.

National product specifications may vary.

These materials are provided by SAP SE or an SAP affiliate company for informational purposes only, without representation or warranty of any kind, and SAP SE or its

affiliated companies shall not be liable for errors or omissions with respect to the materials. The only warranties for SAP SE or SAP affiliate company products and

services are those that are set forth in the express warranty statements accompanying such products and services, if any. Nothing herein should be construed as

constituting an additional warranty.

In particular, SAP SE or its affiliated companies have no obligation to pursue any course of business outlined in this document or any related presentation, or to develop

or release any functionality mentioned therein. This document, or any related presentation, and SAP SE’s or its affiliated companies’ strategy and possible future

developments, products, and/or platform directions and functionality are all subject to change and may be changed by SAP SE or its affiliated companies at any time

for any reason without notice. The information in this document is not a commitment, promise, or legal obligation to deliver any material, code, or functionality. All forward-

looking statements are subject to various risks and uncertainties that could cause actual results to differ materially from expectations. Readers are cautioned not to place

undue reliance on these forward-looking statements, which speak only as of their dates, and they should not be relied upon in making purchasing decisions.

































http://global12.sap.com/corporate-en/legal/copyright/index.epx




Unit 6: SAP Web Dispatcher Integration with Other

Systems


No changes required at the ABAP back end.

iView (System Object, actually) at the EP should point to

the SAP Web Dispatcher.

SAP Web Dispatcher configured for multiple systems:

– wdisp/system_conflict_resolution = 1

– wdisp/system_0 = SID=<ABAP>, …,

SRCURL=/sap;/nwbc

– wdisp/system_1 = SID=<EP>, …, SRCURL=/

SAP Web Dispatcher Integration with Other SystemsSAP Enterprise Portal + ABAP back end


Access to the topology information has to be enabled

manually as of SAP HANA SPS 09 rev. 95

(SAP Note 2146931).



– wdisp/system_0 = SID=<HANA>, XSSRV=<HANA>,

SRCURL=/sap/hana

– wdisp/system_1 = SID=<ABAP>, …,

SRCURL=/sap;/nwbc

SAP Web Dispatcher Integration with Other SystemsSAP HANA / SAP HANA XS





– wdisp/system_0 = SID=<frontend with Fiori and NW GW>, ...,

SRCURL=/sap/opu/odata;/sap/public;/sap/bc

– wdisp/system_1 = SID=<backend with INA search>, ...,

SRCURL=/sap/es

– wdisp/system_2 = SID=<HANA>, ...,

SRCURL=/sap/hba;/sap/hana;/sap/bi;/sap/viz;/sap/vi;/sap/ui5

SAP Web Dispatcher Integration with Other SystemsSAP Fiori (+ SAP NetWeaver Gateway 2.0) + SAP HANA + INA search


wdisp/system_X = SID=EXT, EXTSRV=<list>, …

Examples:

– EXTSRV=http://srv1.external.com:8080;http://srv2.external.com:8080

– EXTSRV=https://srv1.other.com;https://srv2.other.com;https://srv3.other.com

All requests considered as stateless. Add “STICKY=true” for session persistence.

Simple round robin (one request per server).

Static list of servers.

SAP Web Dispatcher Integration with Other SystemsExternal, non-SAP systems

Clients Web Disp.

srv1.external.com

srv2.external.com


[email protected]

Thank you.

week 3: icm and sap web dispatcher services unit …...the web admin page documentation references...

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