Changing the number of mail and write scanning threads

Products

• Mail Security for Domino

Issue/Introduction

This article contains information on how to change the number of scanning threads opened by Symantec Mail Security for Domino (SMSDOM).

Resolution

The following information is also available information from SMSDOM's Implementation Guide.

Modifying the number of processing threads

Mail Security automatically configures the optimum number of processing threads. The minimum number of threads is two per processor.
The maximum number of threads is four per processor. The default configuration ensures the best performance for your Lotus Domino server.
You should not need to modify the number of processing threads.

Warning: If you are uncertain about how a change to the number of processing threads might affect your Domino server, maintain the default settings.
Modifying the number of processing threads could result in an adverse affect on server performance. Contact Technical Support for assistance.

To modify the number of processing threads

1. Turn off the Domino server.
2. In the Domino program directory, make a backup copy of the Notes.ini file.
3. Open Notes.ini in a text editor.
4. Add the following settings:
   SAVMailThreads=(value)
   SAVWriteThreads=(value)
       ...where (value) is the newly computed number of threads.
5. Save the Notes.ini file.
6. Close the text editor.
7. Start the Domino server.

Example of threads configuration:

System with four Quad Core CPUs and maximum number of threads per processor should be configured - 4 threads per CPU. SMSDOM would use 128 threads in total and possibly more than 1.2 GB of RAM only to handle the 'idle' threads. This is calculated as follows:

4 x 4 physical CPUs x 4 cores in CPU    >>>    SAVMailThreads=64
4 x 4 physical CPUs x 4 cores in CPU    >>>    SAVWriteThreads=64

total number of threads = SAVMailThreads + SAVWriteThreads

 

If the CPU and Memory footprints of SMSDOM are impacting negatively the server's performance, the following options could be considered to resolve the situation:

• Upgrading server's physical memory
• If server is a 32-bit system, features such as PAE (Physical Address Extension) to address more than 4GB of memory
• Using a 64-bit Operating System

 

PLEASE NOTE:

1. The total amount of memory used by the SAVMailThreads and the SAVWriteThreads is also influenced by the maximum memory per thread.
   This is a setting that can be found in the settings document (SAV.NSF) under 'Threat/Security Risk > Basics > "Maximum memory to use per thread for extracting attachments".
   The default is 20 MB per thread.
    
2. Setting the SAVMailThreads/SAVWriteThreads in Notes.ini configures a limitation for the total number of threads. It is not the number of threads per processor.
    
3. Setting the Mail or Write threads to "1" is allowed. However, it may decrease the overall server performance below acceptable levels.
4. Calculation of thread numbers doesn't take HT feature into account, threads are calculated based on physical cores of CPUs