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From Patrick Hunt <ph...@apache.org>
Subject Re: Debugging help for SessionExpiredException
Date Fri, 11 Jun 2010 15:37:56 GMT
Session expiration is due to the server not hearing heartbeats from the 
client. So either the client is partitioned from the server, or the 
client is not sending heartbeats for some reason, typically this is due 
to the client JVM gc'ing or swapping.

Patrick

On 06/10/2010 04:14 PM, Ted Dunning wrote:
> Uh.... the options I was recommending were for your CLIENT.  You should have
> similar settings on ZK, but it is your client that is likely to be pausing.
>
> On Thu, Jun 10, 2010 at 4:08 PM, Jordan Zimmerman<jzimmerman@proofpoint.com
>> wrote:
>
>> The thing is, this is a test instance (on AWS/EC2) that isn't getting a lot
>> of traffic. i.e. 1 zookeeper instance that we're testing with.
>>
>> On Jun 10, 2010, at 4:06 PM, Ted Dunning wrote:
>>
>>> Possibly.
>>>
>>> I have seen GC times of>  4 minutes on some large processes.  Better to
>> set
>>> the GC parameters so you don't get long pauses.
>>>
>>> On http://wiki.apache.org/hadoop/ZooKeeper/Troubleshooting it mentions
>> using
>>> the "-XX:ParallelGCThreads=8 -XX:+UseConcMarkSweepGC" options.  I
>> recommend
>>> adding
>>>
>>>     -XX:+UseParNewGC
>>>     -XX:+CMSParallelRemarkEnabled
>>>     -XX:+DisableExplicitGC
>>>
>>> You may want to tune the actual parameters of the GC itself.  These
>> should
>>> not be used in general, but might be helpful for certain kinds of
>> servers:
>>>
>>>     -XX:MaxTenuringThreshold=6
>>>     -XX:SurvivorRatio=6
>>>     -XX:CMSInitiatingOccupancyFraction=60
>>>     -XX:+UseCMSInitiatingOccupancyOnly
>>>
>>> Finally, you should always add options for lots of GC diagnostics:
>>>
>>>     -XX:+PrintGCDetails
>>>     -XX:+PrintGCTimeStamps
>>>     -XX:+PrintTenuringDistribution
>>>
>>> On Thu, Jun 10, 2010 at 3:49 PM, Jordan Zimmerman<
>> jzimmerman@proofpoint.com
>>>> wrote:
>>>
>>>> If I set my session timeout very high (1 minute) this shouldn't happen,
>>>> right?
>>>>
>>
>>
>

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