tomcat-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Nicolas Sarazin <nicolas.sarazin....@gmail.com>
Subject Re: mod_jk/1.2.32 - Error connecting to Tomcat only on one page
Date Mon, 24 Sep 2012 11:54:31 GMT
Hi Christopher,

And thank you for this invaluable information !

I shall continue the discussion if the problem persists after the
update of my configuration.

Nicolas SARAZIN

2012/9/21 Christopher Schultz <chris@christopherschultz.net>:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Nicholas,
>
> On 9/21/12 4:14 AM, Nicolas Sarazin wrote:
>> Ok for all versions upgrades, I put it in my todo list ! It is a
>> customer environment, I can't make it immediately.
>
> That's okay, but you need to be ready when your customer says "hey,
> Tomcat 5.5.x is no longer supported: we need to upgrade".
>
>>> Christopher Schultz wrote:
>>>
>>> Do you have anything else? If not, why bother with Apache httpd?
>>
>> Yes, we have lot of directives (using mod_cache, mod_proxy, ...).
>> In reality, I have about twenty VirtualHost.
>
> Fair enough: it's always worth asking. Lots of people think that
> Apache httpd is, for some reason, required.
>
>>> What MPM are you using? If you are using prefork, then your
>>> connection_pool_size is all wrong. Generally speaking, you
>>> should allow mod_jk to determine its own value for
>>> connection_pool_size when using Apache httpd.
>>>
>>> How many backend Tomcat servers do you have? Looks like one.
>>>
>>> Let's assume you are using threaded MPM in httpd (otherwise the
>>> value for 1200 is insane) and you are using only one backend
>>> Tomcat server.
>>>
>>> You have 1200 connections configured in httpd
>>> (connection_pool_size), but Tomcat can only accept 600 of them
>>> (maxThreads) at any given time. You have used backlog=8192 to
>>> cover this up so things become even more confusing.
>>
>> I using prefork. Indeed, in Apache documentation : "Do not use
>> connection_pool_size with values higher then 1 on Apache 2.x
>> prefork or Apache 1.3.x!". It's better to delete it or to put its
>> value to 1 ?
>
> I would delete the option altogether - per the documentation - and
> allow mod_jk to select the appropriate setting.
>
>> What problems can arise with mpm prefork and connection_pool_size >
>> 1 ?
>
> A big waste of memory and a lot of needless overhead. I dunno how
> mod_jk manages its connections, but it might immediately open 1200
> connections per prefork process to your backend, which can waste a lot
> of resources, too.
>
>>>> Usually, it's work correctly, but sometime, only on certain
>>>> pages, woker can't connect to Tomcat. In my logs files, I have
>>>> :
>>>
>>> I think it's only a coincidence that /page2 consistently gives
>>> you 500-response errors, here. Try looking at a wider section of
>>> your httpd access log to determine if there really is something
>>> special about /page2 (of course, /page2 could be returning
>>> 500-response itself: you might want to check on that).
>>
>> This page was in error 500 in acces log between 19:12:27 and
>> 20:04:39.
>>
>>>> How can we explain this behavior ?
>>>
>>> There are lots of explanations for what you are seeing.
>>>
>>> A few questions:
>>>
>>> 1. Do you really need Apache httpd at all? 2. Can you configure
>>> cping/cpong for connection liveness testing? 3. Have you tried
>>> disabling AJP connection re-use altogether? localhost
>>> communication is fast fast fast.
>>
>> 1 - Yes :) 2 - Yes, but not immediately 3 - I don't, but I am going
>> to test !
>
> Good luck.
>
> - -chris
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG/MacGPG2 v2.0.17 (Darwin)
> Comment: GPGTools - http://gpgtools.org
> Comment: Using GnuPG with Mozilla - http://www.enigmail.net/
>
> iEYEARECAAYFAlBc4BMACgkQ9CaO5/Lv0PA/8gCgm0FxMnBA7t5lxZzB5t5rZMPg
> tAkAniqoOQWd7ttK+COk9w0I1g9HHt6R
> =59/Q
> -----END PGP SIGNATURE-----
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org


Mime
View raw message