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We have 2 identical (as far as we can tell) apache servers in a load balanced configuration. The servers are behind a hardware load balancer. One of the 2 servers, during periods of relatively high load, routinely exhibits 50% higher process counts than the other server.

The obvious culprit would be a misconfiguration of the load balancer, but the amount of traffic that each server sees is nearly identical (<1% different). The server statistics (cpu utilization) are identical or nearly identical as well.

Apache configurations (the /etc/httpd directory) are identical as well. I suspected a longer tcp timeout on the one server but the thresholds are identical.

What other factors could be contributing?

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You could start by telling us how you're doing your load balancing... (what kind of "hardware load balancer"? What mechanism does it use for distributing connections? etc.) – voretaq7 Jun 17 '13 at 21:00
Its a barracuda web applicaiton firewall. Its using stateless round robin LB. I compared the traffic (both from apache stats and weblogs) and the traffic quantity equally balanced between severs. – Joel Jun 18 '13 at 13:57

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