apache/httpd responds slower under EL6.1 than EL5.6 (centos)
- by daniel
I've read through other threads on performance differences between RHEL6 and RHEL5, but none seem a tight match to mine.
My issue manifests itself in slightly slower average response time (20ms) per request. I have about 10/10 servers of the same hardware spec with Cent6.1 and Cent5.6. The issue is consistent across the group.
I am running Ruby on Rails with Passenger.
Apache config is identical (checked out from the same SVN repo)
Ruby and Passenger are identical builds.
Application is identical and being served traffic round robin.
mod_worker
An interesting clue from server-status: The Cent6.1 servers have a steady 20-40 threads in the "Reading Request" state while the Cent5.6 servers have around 1. I'm graphing this so I can see it trend over time.
I also have a bunch of much newer machines that are significantly faster and are running Cent6.1. They dust all the older machines in response time, but I can see they also have a steady 20-40 threads in the "Reading Request" state. This makes me believe I can get their response time down, if I can figure out what is holding up these requests.
My gut is telling me that I need to tune some network setting in sysctl, but I haven't figured it out yet. Help is appreciated.