After launching our new web servers in July, 2015 with ColdFusion 11 there were complaints that pages and applications were taking “forever” to load. During our troubleshooting, we tried to eliminate as many variables as we could to narrow down the problem, and yet, no matter what we tried, sometimes the application would be fast (~2 seconds) and sometimes very slow (~20 seconds) for the same exact action. Nothing we tried, including doubling the amount of RAM and the number of CPUs had any effect. The only thing we knew for sure was that when the slowness manifested itself, the CPU would spike to 100% and sustain that level for some time. Once the CPU went back to normal levels the application would run at a normal speed again.

Through some lucky searching I found this blog post that suggested it was the seed generator. This issue is limited to Linux servers. We changed the JVM settings via the ColdFusion administrator to use the non-blocking seed generator instead and have not had the problem since. I wanted to share this in the hopes that others who have this problem will find the solution faster than we did.