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Accumulo >> mail # user >> Determining the cause of a tablet server failure


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Re: Determining the cause of a tablet server failure
I agree with John Vines.

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Christopher L Tubbs II
http://gravatar.com/ctubbsii
On Wed, Feb 27, 2013 at 12:32 PM, John Vines <[EMAIL PROTECTED]> wrote:
> I don't like the idea of blending manual logging with log4j in a single
> file. It's in the .err file already, I don't think anything else is
> necessary.
>
>
>
> On Wed, Feb 27, 2013 at 3:27 PM, Adam Fuchs <[EMAIL PROTECTED]> wrote:
>>
>> So, question for the community: inside bin/accumulo we have:
>>   -XX:OnOutOfMemoryError="kill -9 %p"
>> Should this also append a log message? Something like:
>>   -XX:OnOutOfMemoryError="kill -9 %p; echo "ran out of memory >>
>> logfilename"
>> Is this necessary, or should the OutOfMemoryException still find its way
>> to the regular log?
>>
>> Adam
>>
>>
>>
>> On Wed, Feb 27, 2013 at 3:17 PM, Mike Hugo <[EMAIL PROTECTED]> wrote:
>>>
>>> I'm chalking this up to a mis-configured server.  It looks like during
>>> the install on this server the accumulo-env.sh file was copied from the
>>> examples, but rather than setting editing it to set the JAVA_HOME,
>>> HADOOP_HOME, and ZOOKEEPER_HOME, the entire file contents were replaced with
>>> those env variables.
>>>
>>> I'm assuming this caused us to pick up the default (?)  _OPTS settings
>>> rather than the correct ones we should have been getting based on our server
>>> memory capacity from the examples.  So we had a bunch of accumulo related
>>> java processes all running with memory settings that were way out of whack
>>> from what they should have been.
>>>
>>> To solve it I copied in the files from the conf/examples directory again
>>> and made sure everything was set up correctly and restarted everything.
>>>
>>> We never did see anything in out log files or .out / .err logs indicating
>>> the source of the problem, but the above is my best guess as to what was
>>> going on.
>>>
>>> Thanks again for all the tips and pointers!
>>>
>>> Mike
>>>
>>>
>>> On Wed, Feb 27, 2013 at 11:24 AM, Adam Fuchs <[EMAIL PROTECTED]> wrote:
>>>>
>>>> There are a few primary reasons why your tablet server would die:
>>>> 1. Lost lock in Zookeeper. If the tablet server and zookeeper can't
>>>> communicate with each other then the lock will timeout and the tablet server
>>>> will kill itself. This should show up as several messages in the tserver
>>>> log. If this happens when a tablet server is really busy (lots of threads
>>>> doing stuff) then the log message about the lost lock can be pretty far back
>>>> in the queue. Java garbage collection can cause long pauses that inhibit the
>>>> tserver/zookeeper messages. Zookeeper can also get overwhelmed and behave
>>>> poorly if the server it's running on swaps it out.
>>>> 2. Problems talking with the master. If a tablet server is too slow in
>>>> communicating with the master then the master will try to kill it. This
>>>> should show up in the master log, and also will be noted in the tserver log.
>>>> 3. Out of memory. If the tserver JVM runs out of memory it will
>>>> terminate. As John mentioned, this will be in the .err or .out files in the
>>>> log directory.
>>>>
>>>> Adam
>>>>
>>>>
>>>>
>>>> On Wed, Feb 27, 2013 at 12:10 PM, Mike Hugo <[EMAIL PROTECTED]> wrote:
>>>>>
>>>>> After running an ingest process via map reduce for about an hour or so,
>>>>> one of our tserver fails.  It happens pretty consistently, we're able to
>>>>> replicate it without too much difficulty.
>>>>>
>>>>> I'm looking in the $ACCUMULO_HOME/logs directory for clues as to why
>>>>> the tserver fails, but I'm not seeing much that points to a cause of the
>>>>> tserver going offline.   One minute it's there, the next it's offline.
>>>>> There are some warnings about the swappiness as well as a large row that
>>>>> cannot be spit but other than that, not much else to go on.
>>>>>
>>>>> Is there anything that could help me figure out *why* the tserver died?
>>>>> I'm guessing it's something in our client code or a config that's not
>>>>> correct on the server, but it'd be really nice to have a hint before we