[openstack-dev] Scheduler proposal

Thierry Carrez thierry at openstack.org
Mon Oct 12 10:30:09 UTC 2015

Clint Byrum wrote:
> Excerpts from Joshua Harlow's message of 2015-10-10 17:43:40 -0700:
>> I'm curious is there any more detail about #1 below anywhere online?
>> Does cassandra use some features of the JVM that the openJDK version 
>> doesn't support? Something else?
> This about sums it up:
> https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/service/StartupChecks.java#L153-L155
>     // There is essentially no QA done on OpenJDK builds, and
>     // clusters running OpenJDK have seen many heap and load issues.
>     logger.warn("OpenJDK is not recommended. Please upgrade to the newest Oracle Java release");


This is one of the reasons I'm generally negative about Java solutions
(Cassandra or Zookeeper): the free software JVM is still not on par with
the non-free one, so we indirectly force our users to use a non-free
dependency. I've been there before often enough to hear "did you
reproduce that bug under the {Sun,Oracle} JVM" quite a few times.

When the Java solution is the only solution for a problem space that
might still be a good trade-off (compared to reinventing the wheel for
example), but to share state or distribute locks, there are some pretty
good other options out there that don't suffer from the same fundamental

Thierry Carrez (ttx)

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