[Mono-list] Some issues with mono 2.0
jit at occams.info
Mon Sep 29 13:53:40 EDT 2008
> "Service Temporary Unavailable" error appears when amount of waiting
> requests reach limit or when waiting requests reach apache timeout?
Yes, both. That is (to be clear), either:
A) A request comes in and the maximum number of requests are already
being processed, so this request waits (it sleeps for short intervals)
until the number of currently-being-processed requests drops below the
maximum. If that doesn't happen within a certain amount of time
(hard-coded in mod_mono), the request is dropped with 503. (Service
B) A request comes in and the maximum number of requests are already
being processed, but there are also already the maximum number of
waiting requests waiting, so this request gets dropped *immediately*
with 503 (Service Temporarily Unavailable).
So I was half-wrong before because I forgot that another way to avoid
503s is to increase the timeout in mod_mono (but as I said, it's
hard-coded) so requests can wait longer. But it's already fairly long
--- 20 seconds or something.
- Josh Tauberer
"Yields falsehood when preceded by its quotation! Yields
falsehood when preceded by its quotation!" Achilles to
Tortoise (in "Godel, Escher, Bach" by Douglas Hofstadter)
> Joshua Tauberer wrote:
>> Maxim wrote:
>>> Hmm, it seems like we solved problem just partially. With
>>> MonoMaxActiveRequests 10 MonoMaxWaitingRequests 100
>>> settings there are a lot messages like "Maximum number (10) of
>>> concurrent mod_mono requests to
>>> /tmp/mod_mono_dashboard_nike-outdoor.ru_2.lock reached. Droping
>>> request." and some visitors get "Service Temporary Unavailable"
>> Well that's exactly what's going to happen when you limit the
>> number of connections --- the hope is that with a reasonably large
>> MonoMaxWaitingRequests it doesn't happen often.
> So, we should to increase MonoMaxWaitingRequests ? "Service
> Temporary Unavailable" error appears when amount of waiting requests
> reach limit or when waiting requests reach apache timeout?
>>> Is option "MonoMaxWaitingRequest" implemented?
>> Yes. (I did it myself...)
> Great respect!
>> If you access a page during high load and see your browser waiting
>> with no response for a while, that's MonoMaxWaitingRequest in
>> action holding onto the request until it gets a chance to be
> Yes, exactly. But sometimes after waiting browser get response
> "Service Temporary Unavailable".
> Thanks again for your help!
> All the best, Max Karavaev
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