Re: [Sheflug] memory usage in linux

["David Willington" <david.willington@xxxxxxxxxxxx>]

> The thing to do is find out the cause of the crash, which may well be
> easier said than done. Is it a certain application, or does the entire
> OS melt?
I can't remember exactly what happened. The main problem I have is that
each time I ask a teacher to test it with a class and it falls flat I end
up with more egg on my face. They're friendly but their patience is
limited! From what I remember the whole thing crashed. Even a terminal
failed to respond and I ended up pressing the reset button. If the network
is the issue, I think what may be happening is that pupils are not logging
on quickly enough, are hitting the submit button again and again (which as
I understand it forces the browser to send repeat requests to apache which
it has to handle). Presumably if the network is slow, apache threads are
having to hang around for a long time to handle the slow connections,
maybe new threads are created each time submit is hit. I've set the apache
timeout (I forget the exact directive) to 10 mins and suggested that
teachers get pupils to log on (at least enter their details and hit submit
once) then have a 'this is what we're doing this lesson' sort of chat, by
which time with luck everyone will be looking at the moodle homepage. At
least that's the latest theory. I'm also trying to set up ntlm
authentication so that, hopefully, as they log on to the network they will
simultaneously be logged on to moodle. I'm not expecting this to be any
quicker but one very long wait seems better (from a teaching point of
view) than two long waits. Unfortunately ntlm support doesn't seem to be
straightforward to set up.


>
>>              total       used       free     shared    buffers
>> cached
>> Mem:       3116476    1928016    1188460          0     210076
>> 1423932
>> -/+ buffers/cache:     294008    2822468
>> Swap:      2048276       7064    2041212
>
> That looks fine to me. Might be worth monitoring the free values as
> usage varies, so you can get some kind of idea of how it changes as
> different numbers of people are using the system, but it doesn't look
> like memory issues to me.
I've been hitting it with ab tests (from localhost), and it behaves as I
expected it to, although these haven't made any connections to the
database (mysql). I've not managed to find a mysql benchmark tool I can
get to work - I'm sure there is one though

Thanks for all your help

David


> Cheers,
>
> Alex.
>
>
> _______________________________________________
>         Sheffield Linux User's Group
>   http://www.sheflug.org.uk/mailfaq.html
>  GNU - The choice of a complete generation
>



_______________________________________________
        Sheffield Linux User's Group
  http://www.sheflug.org.uk/mailfaq.html
 GNU - The choice of a complete generation