tomcat-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From הילה <>
Subject Re: Application crash after Migrate to different ESX
Date Wed, 18 May 2011 08:20:03 GMT

this behavior occur even when I'm disconnecting the Network card from the VM
settings and connecting it again.
afterwards, the keep alive is alternately unavailable. looks like it's not
always trying to approach the DB opened wireshark and saw that ip.addr==DB
IP ADDRESS is not always showing results when the keep alive is unavailble =
he's not trying to get to the DB at all, I think.

it all sorts out after I restart the tomcat service. this is why I think it
does related to tomcat.


18 במאי 2011 00:06, From Hila <>:

>>>> I'll try explaining it differently.
>>>>  we use smart keep alive with this application. the smart keep alive
>>> does a
>>> connection to the DB, query something that relates to the application,
>>> and
>>> if everything turned out good, it returns state OK. if not ok, as in this
>>> case, it returns error page 500 which means- unable to run the specified
>>> query, because unable to connect to DB due to server side issue, or
>>> because
>>> DB unavailable and such.
>>> so after migrate, it disconnect the users, and the keep alive is
>>> unavailable
>>> (page 500), then it's available (state ok), then after couple of seconds
>>> again unavailable. then it returns to state ok and stay like this
>>> (scenario
>>> 1) or stays unavailable (page 500) until I restart the tomcat service and
>>> then display state ok for good (scenario 2).
>>>  ...
>> I have no idea what this "smart keep alive" is, of which you talk above.
>>  Is that a part of Tomcat ? If it returns an "error page 500", then it
>> sounds more like a webserver in its own right.
>> ..and also taking into account your other posts about this issue :
>> We would of course try our best to help you here, but this is a mailing
>> list dedicated to Tomcat, and it sounds as if the problem you are having is
>> more about a more general problem of infrastructure and combining different
>> pieces together, of which only one is Tomcat.
>> I believe that questions and answers on this list are not the appropriate
>> way to resolve that kind of problem, and I believe that what you really need
>> is some expert help, from someone who really understands the different
>> pieces and how they (should) fit together.
>> Maybe these external consultants to which you referred ?
>> To give you an idea : you said initially that the problem occurs when a VM
>> is migrated (by Vmware) to another ESX server, and that when that happens
>> the network connections are lost.  Well, I am not even sure that this is
>> supposed to happen, if Vmware is configured correctly.  So you may be
>> looking in the wrong place for a solution, to start with.
>> better to call in an expert, you would probably save time and money in the
>> end.
>> I talked to VM experts, they say that network disconnection can happen for
>> a sec, but the application shouldn't be affected by it as it is.
> smart keep alive is a keep alive in its ordinary meaning. it called smart
> cause it's not checking only the port and its availability, but also a
> connection to the DB and functionality via DB query of some sort.
> I do believe it relates to tomcat since in other machines that we migrated
> and don't have tomcat, our application doesn't crash.
> I also don't think this happened in every migrate we ever did. so I don't
> understand why it began to happen.
> the guys here in the list are helpful, so i'll give it a try. if no one can
> help, i'll try different ways/methods/approach :]
> Thanks
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail:
>> For additional commands, e-mail:

  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message