Setting scanning threads and number of scan processes

Mail Security lets you set the number of scan processes to control scanning speed and performance. The default is configured using the following formula: (number of processors) x 2 + 1. Accept the default unless you have a compelling reason to do otherwise.
Mail Security considers a hyper-threaded processor as more than one processor. For example, if you have a dual hyper-threaded processor on your computer, Mail Security calculates the number of scanning processes as follows:
Number or processors (4) x 2 + 1 = 9
When the load is heavy, all nine scanning processes scan messages. Increasing the number of scan processes can consume a lot of memory if the server has few resources. This situation can severely affect the performance of your Exchange server.
Configure the number of scan processes based on the actual number of physical processors if you have a hyper-threaded processor on your computer. For example, if you have a dual hyper-thread processor, configure the number of scan processes as follows:
Number of physical processors (1) x 2 +1 = 3
If you use Intel Xeon processors, you must set this value using the formula based on the number of physical processors, instead of the number that is reported by the operating system.
  1. To set scanning threads and number of scan processes
  2. In the console on the primary navigation bar, click
    Admin
    .
  3. In the sidebar under
    Views
    , click
    System Settings
    .
  4. In the
    Number of VSAPI scanning threads
    box, type the number of threads to use for VSAPI scanning.
    The default value is 3.
    This step is applicable only for Exchange Server 2010.
  5. In the
    Number of scan processes
    box, type the number of scan processes.
    The default is configured during installation using the formula 2 times the number of processors plus 1.
  6. On the toolbar, click
    Deploy changes
    to apply your changes.