HTTP 500 Errors Under Load — MaxRequestWorkers Limit Reached in CA Access Gateway (SPS)

Products

• SITEMINDER
• CA Single Sign On Secure Proxy Server (SiteMinder)
• CA Single Sign-On

Issue/Introduction

While running a stress test against CA Access Gateway (SPS), you receive HTTP 500 errors, for example around 16:49.

SPS reports the following in error.log:

[Tue Jun 23 16:49:27.553735 2026] [mpm_worker:error] [pid 2864592:tid 140028185963584] AH00286: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting
[Tue Jun 23 16:49:28.554088 2026] [mpm_worker:error] [pid 2864592:tid 140028185963584] AH00287: server is within MinSpareThreads of MaxRequestWorkers, consider raising the MaxRequestWorkers setting

Resolution

To resolve this, tune the following three parameters step by step, each set to a slightly higher value than the preceding one:

MaxRequestWorkers < ajp13.max_threads < http_connection_pool_max_size

Also ensure the OS open file descriptor limit is sufficient to support the increased number of threads, if CA Access Gateway (SPS) runs on Linux (1)(2).

Benchmark the environment by raising the load incrementally, correcting each error as it occurs, until the targeted load is reached (3).

Additional Information

1. CA Access Gateway (SPS) Linux Tuning How-To
   
   
2. CA Access Gateway (SPS): Commonly Tuned Parameters
   
   
3. SiteMinder Performance Tuning