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Web Agent IPC Error


Article ID: 50269


Updated On:


CA Single Sign On Secure Proxy Server (SiteMinder) CA Single Sign On SOA Security Manager (SiteMinder) CA Single Sign-On



We're running a Web Agent, and in the Web Server's log, we get this
kind of error in the Web Agent log :

  [14/Apr/2011:14:47:06] [Error] [CA WebAgent IPC]
  [10054][CSmSharedSegment::smalloc] Error allocating shared memory
  segment using key 0x6cc7b0a7 - File exists (17)

  [14/Apr/2011:14:47:06] [Info] [CA WebAgent IPC] [10054]
  [CSmSem::SemRm] Removed semaphore 45285378

  [14/Apr/2011:14:47:06] [Error] SiteMinder Agent

  PID Cache error.

  Failed to initialize PID Cache

How can we fix that ?




The following startup error messages:

   "PID Cache error"

is generated when web agent or LLAWP process is unable to create or
attached to its required semaphores and shared memory segments. These
are system resources required by the web agent to communicate between
itself and LLAWP process to pass information.

  "Error allocating shared memory segment using key" 

is a failure of this type can be created by the failure to create the
segments or the segments being subsequently removed. As this is a
startup issue it points to there being an issue with creation and the
most likely reasons for this are:

  - Unavailable system resources (the system settings are too low);

  - Permission issues (old resources are left around with different
    permissions or another web agent created the system resources with
    the same key);




To try resolving the issue, you can try the following:

  - Verify that shared memory and semaphores leftover from the web
    server that would be interfering:

    - Shut down the web server;
    - Make sure the LLAWP process is shut down;

    - Check for shared memory and semaphores leftover from the web
      server using these commands:

      - ipcs -s : list semaphores
      - ipcs -m : list shared memory
      - ipcrm -s : remove semaphores
      - ipcrm -m : remove shared memory

    - Then remove any shared memory or semaphores for this
      instance. Look in the Web Server error log for the semaphore and
      shared memory keys. Those are the ones which need to be removed;

    - Start the web server;

  - Check if the system has enough memory to handle the resource and
    session caches;

  - If you have increased the session/resource cache size, then change
    them to default;

  - If you are using the default values, then decrease to 0;

  - Then restart the Web Server;

Session and resource cache size parameters are:


The idea behind decreasing those values to 0 is to check whether your
system has enough memory or not. There might be a loss of performance
while those values are at 0, because there will be no caching. However
if this issue disappears, then it means that you should add some
memory to the system, or reduce the cache size to a lower level if
adding memory isn't possible.