Identifying Slow WebSphere Startups or Admin Functions relating to INET6 Hostname Lookup
DavidLaraman 270004BMB2 Comments (3) Visits (14688)
If you are experiencing a very Slow WebSphere Application Server Startup and/or possibly WSAdmin command executions or Administrative Console operations are taking a very long time to complete, regardless of what product version you are currently running, the issue could be IP Address lookup and Hostname resolution related. This is contingent upon finding supporting evidence of relevant java
WebSphere defaults to the IPv6 protocol stack from version 6 refresh pack 2 v6.0.2 product releases onwards (v6.0.2.x, v6.1.x, v7.0.x, v8.0.x, v8.5.x). In some cases the existing DNS servers for a production environment are still running the older IPv4 protocol stack, which is 32 bit architected code not supporting the larger range of internet protocol addresses currently available in the INET6 specification.
This mismatch in protocol stacks directly impacts DNS lookup operations causing delays for the ip address and hostname resolution.
To verify if you are a candidate for the issue being described, simply collect a series of javacores or threaddumps using the kill -3 command, preferably spaced a few minutes apart, when Starting WebSphere or executing WSAdmin command that is performing slow and taking a long time to complete.
Using either an ascii text editor or specialized tooling such as IBM Thread and Monitor Dump Analyzer or Wait, look for and locate the Main routine and/or Startup thread and verify the associated Code Stack contains the mentioned INET6 function call or native method at the top of the stack.
e. g. Partial stack frames extracted below from different Javacores collected from (17:01 - 17:08) for the same JVM processID, using the IBM Thread and Monitor Dump Analyzer. Both show similar main thread routines caught up in at java