[Deploying Sakai] slow startup in OS X; IPv6 implicated

Charles Hedrick HEDRICK at RUTGERS.EDU
Sat Feb 6 09:37:17 PST 2010

I have a Mac Pro for my development system. It starts up Sakai in 49 sec, much faster than our production servers (where it's several minutes). This is our whole production load, not a cut-down development image. However once it claims to be started, it rejects connections for a couple of minutes and then starts accepting only some of them. Based on some online discussions, I believe I have found a resolution: add -Djava.net.preferIPv4Stack=true to the JVM options. Apparently it tries to use IPv6 and runs into problems. This should only be an issue if your system has IPv6 enabled, though I think that's the default. There seems to be a problem with the way tomcat handles IPv6. It has recently been resolved in Tomcat 6.

The following deals with the problem when using the native APR interface: https://issues.apache.org/bugzilla/show_bug.cgi?id=43327.  To my knowledge we're not doing that. The problem may well be OS-specific. 

Our production systems are using Solaris, but they don't have IPv6 enabled. So we wouldn't see this in production. At some point we do want to be able to use IPv6. However we'll be moving to a setup where the load balancers terminate the SSL connection, so it may only matter if the load balancers can handle IPv6.

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