I just upgraded from CentOS 5.5 to CentOS 5.6, while running Squid v3.1.12.1 in both environments, and somehow created a race condition in the process. Besides updating the 200+ software packages that are the difference between 5.5 and 5.6, I configured and enabled DNSSEC on my nameserver.
What I see now is that Squid started at boot time uses 100% CPU, with no traffic at all, and will stay that way seemingly forever. If I shut down Squid and restart it, all is well. So: Squid started at boot time = bad, Squid started post-boot = good. There is nothing unusual in either the system or Squid logs to suggest what the problem is. Can anyone suggest how to diagnose what Squid is doing/waiting for? Thanks.
