Friday, June 12, 2009

Background documentationHardware Requirements for SAProuter

SAProuter Architecture and Requirement Profile

Since the work of the SAProuter (also with SNC) is mainly I/O-based (input/output), you do not require any especially powerful CPU.

The workload handled by the SAProuter is determined by the number of open connections.

If over 800 connections have to be maintained, we recommend that you start new SAProuter processes with Option -Y . This distributes the load across several processes and reduces the risk of any problem occurring (if a problem does occur, it never affects all the open connections.) The following rule of thumb applies to many connections: 1 SAProuter per 500 connections.

Alternatively to option -Y you can also set a script that monitors the SAProuter process and restarts the SAProuter (soft shutdown with Option -p, then restart), as soon as a certain number of connections is exceeded, or when the message

Maximum number of clients reached is written for the first time.

Since the SAProuter process is running in one thread (single threaded) and is often busy with I/O calls or with host name resolutions, a computer with one CPU manages well with several SAProuter processes running in parallel.

Recommended Hardware

For an SAProuter with 3000 parallel connections between SAP GUIs and application servers, transferring an average volume of data, a small number of file downloads and uploads (approximately 8kB data transfer in both directions per connection and per 10 seconds), we recommend:

  • Quick network adapter (very important)

  • 2 hyper-threading (HTT) CPUs with 2GHz tact frequency

  • 512 MB RAM

  • 50 MB free space on the hard drive for SAProuter and configuration

  • Hard drive space for log files


For 3000 users we estimate six SAProuter processes (set Option -C to 1000).

Each of these processes requires 4.5 MB of memory, and 9% of a two-way HTT 3 GHz CPU, if you assume one third of the CPU workload is for the users and two thirds for the system. The six SAProuter processes together require approximately 30 MB and 55% of the CPU.

Sometimes it takes a few seconds to determine the host name from the IP address (reverse lookup), and during this time the process is blocked. The cause is usually an error in the DNS configuration. Users will notice these delays particularly if the workload on the SAProuter is large. Use Option -D, to prevent this happening.

Recommended Start Options

Start the SAProuter as follows:

saprouter -r -K -Y 0 -C 1000 -D -G -J 2000000

More Information

For information about operating the SAProuter under Windows see SAP note 734095.

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