[erlang-questions] Investigate an infinite loop on production servers
Dmitry Kolesnikov
dmkolesnikov@REDACTED
Fri May 24 10:31:17 CEST 2013
Hello,
I am not aware of a single flag to limit the memory like in Java.
You can try to configure memory allocation
http://www.erlang.org/doc/man/erts_alloc.html
One of the freeze reason might be a huge crash_dump.
See the flags at bottom of page how to tune its behaviour
http://www.erlang.org/doc/man/erl.html
If you switch off a swap it helps to observe OOM.
Would you share to the list app you running applications?
application:which_applications()
- Dmitry
On May 24, 2013, at 11:13 AM, Morgan Segalis <msegalis@REDACTED> wrote:
> The problem is that the VM freezes completely, it does not generate a crash dump
>
> Is there a way to limit the memory that a VM can allocate, so the server is not overwhelmed in order to create a crash dump ?
>
> Le 24 mai 2013 à 02:00, Vance Shipley <vances@REDACTED> a écrit :
>
>> Have you analyzed the crash dump file with the crash dump viewer?
>> On May 24, 2013 3:00 AM, "Morgan Segalis" <msegalis@REDACTED> wrote:
>> Yeah you got that right ! leaking at a huge rate at some point !
>>
>> - The number of Fd - I don't get close to the max
>> # cat /proc/sys/fs/file-nr
>> 3264 0 6455368
>>
>> - On the production server there is only the erlang node, no other service…
>> The beam.smp was through the roof at 300% CPU and 97% RAM
>> The weird thing is that it got there in a second, I was looking at it when it happens.
>>
>> - It has happened with 2000 connections, 4000 connections, and 10000 connections… 5 min after start, 5hours after start.
>>
>> I really can't find a pattern here…and I'm becoming a little desperate.
>>
>> Thank you for your help again.
>>
>> Morgan.
>>
>> Le 23 mai 2013 à 23:20, Dmitry Kolesnikov <dmkolesnikov@REDACTED> a écrit :
>>
>>> You system definitely leaking some resources :-/
>>> - Check number of used FD(s) may be you exceeded limit there
>>> - What was overall system memory / cpu utilisation before crash?
>>> - Check how many connections you got before crash, may be you can reproduce it at dev
>>>
>>> - Dmitry
>>>
>>> On May 24, 2013, at 12:13 AM, Morgan Segalis <msegalis@REDACTED> wrote:
>>>
>>>> Ok, it finally got into the infinite loop…
>>>>
>>>> And of course, the node on which I was running etop could not give me anymore since it got disconnected from the production node.
>>>>
>>>> So back to square one… no way to investigate correctly so far :-/
>>>>
>>>> Morgan.
>>>>
>>>> Le 23 mai 2013 à 16:34, Morgan Segalis <msegalis@REDACTED> a écrit :
>>>>
>>>>> Yeah that what I'm doing right now, but of course, when I'm monitoring it, it won't crash, only when I sleep !!
>>>>>
>>>>> I get back to the Erlang list as soon as I have more informations about this.
>>>>>
>>>>> Thank you all !
>>>>>
>>>>> Morgan.
>>>>>
>>>>> Le 23 mai 2013 à 16:30, Vance Shipley <vances@REDACTED> a écrit :
>>>>>
>>>>>> Keep etop running and capture the output to a file (e.g. etop ... | tee stop.log). After it gets into trouble look back and see what was happening beforehand.
>>>>>> On May 23, 2013 6:16 PM, "Morgan Segalis" <msegalis@REDACTED> wrote:
>>>>>> So I should go back to R15B ?
>>>>>>
>>>>>> erlang:memory() gives me
>>>>>>
>>>>>> [{total,1525779584},
>>>>>> {processes,1272881427},
>>>>>> {processes_used,1272789743},
>>>>>> {system,252898157},
>>>>>> {atom,372217},
>>>>>> {atom_used,346096},
>>>>>> {binary,148093608},
>>>>>> {code,8274446},
>>>>>> {ets,1546832}]
>>>>>>
>>>>>>
>>>>>> But keep in mind that right now, there is no infinite loop, or memory issue at this exact time…
>>>>>> It will be more interesting to have that when the VM is asking for 14GB of memory, but when it does, the console is unresponsive, so I can't get anything then.
>>>>>>
>>>>>> Le 23 mai 2013 à 14:39, Dmitry Kolesnikov <dmkolesnikov@REDACTED> a écrit :
>>>>>>
>>>>>>> Right, you do not have many processes. Same time you goes out of memory…
>>>>>>>
>>>>>>> Unfortunately, I had no time play around with R16B at production…
>>>>>>> Could it be some issue with SSL, I re-call there was some complains in the list?
>>>>>>>
>>>>>>> I would use entop to spot the process that has either too much reductions, queue len or heap.
>>>>>>> Once you know they pid you can dig more info about them using erlang:process_info(…) and/or sys:get:status(…)
>>>>>>>
>>>>>>> BTW, What erlang:memory() says on you production node?
>>>>>>>
>>>>>>> - Dmitry
>>>>>>>
>>>>>>> On May 23, 2013, at 3:25 PM, Morgan Segalis <msegalis@REDACTED> wrote:
>>>>>>>
>>>>>>>> No, I was talking about the function I made to investigate which processes I have created, which gives me this output :
>>>>>>>>
>>>>>>>> Dict: {dict,16,16,16,8,80,48,
>>>>>>>> {[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},
>>>>>>>> {{[[{{connector_serv,init,1},[connector_suprc42,connector,<0.42.0>]}|548]],
>>>>>>>> [],
>>>>>>>> [[{{supervisor,connector_sup,1},[connector,<0.42.0>]}|3],
>>>>>>>> [{{connector_serv,init,1},[connector_supssl,connector,<0.42.0>]}|1460],
>>>>>>>> [{{supervisor,casserl_sup,1},[connector,<0.42.0>]}|1],
>>>>>>>> [{{supervisor,pushiphone_sup,1},[connector,<0.42.0>]}|2],
>>>>>>>> [{{pushiphone,init,1},['pushiphone-lite',connector,<0.42.0>]}|3],
>>>>>>>> [{{supervisor,clientpool_sup,1},[connector,<0.42.0>]}|1]],
>>>>>>>> [],
>>>>>>>> [[{{clientpool,init,1},[clientpool_sup,connector,<0.42.0>]}|1],
>>>>>>>> [undefined|4]],
>>>>>>>> [],
>>>>>>>> [[{{supervisor,connector,1},[<0.42.0>]}|1],
>>>>>>>> [{{casserl_serv,init,1},[casserl_sup,connector,<0.42.0>]}|50]],
>>>>>>>> [],[],[],
>>>>>>>> [[{{connector_serv,init,1},[connector_suprc4,connector,<0.42.0>]}|472],
>>>>>>>> [{{ssl_connection,init,1},
>>>>>>>> [ssl_connection_sup,ssl_sup,<0.51.0>]}|
>>>>>>>> 1366],
>>>>>>>> [{unknown,unknown}|3]],
>>>>>>>> [],[],
>>>>>>>> [[{{pushiphone,init,1},['pushiphone-full',connector,<0.42.0>]}|3]],
>>>>>>>> [],
>>>>>>>> [[{{pg2,init,1},[kernel_safe_sup,kernel_sup,<0.10.0>]}|1]]}}}
>>>>>>>> ok
>>>>>>>>
>>>>>>>> I'm very satisfied with supervisor, and I don't think to have the expertise tweaking it...
>>>>>>>>
>>>>>>>> Le 23 mai 2013 à 14:19, Dmitry Kolesnikov <dmkolesnikov@REDACTED> a écrit :
>>>>>>>>
>>>>>>>>>
>>>>>>>>> On May 23, 2013, at 1:04 PM, Morgan Segalis <msegalis@REDACTED> wrote:
>>>>>>>>>
>>>>>>>>>> I have made a little function a while back, getting all processes and removing the processes inited at the beginning…
>>>>>>>>>
>>>>>>>>> Could you please elaborate on that? Why you are not satisfied with supervisor?
>>>>>>>>>
>>>>>>>>> - Dmitry
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> erlang-questions mailing list
>>>>>> erlang-questions@REDACTED
>>>>>> http://erlang.org/mailman/listinfo/erlang-questions
>>>>>>
>>>>>
>>>>
>>>
>>
>
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