Re: [cobalt-users] RaQ3 massive hits - trouble!

[Graeme Fowler <graeme.f@xxxxxxxxxxxxxxx>]

James Riordon wrote:
> Why does the server do this, I can understand it getting slow, but 
> this is ridiculous. Any thoughts on how we might prevent the server 
> from becoming so slow would be really usefull right now.

You'll see this (as I explained in an off-list mail to James) when your
machine is 'thrashing' heavily - ie. swapping memory out to disk so badly
that it backlogs and simply can't keep up with all it's being asked to do.
It's simply a lack of RAM. When the machine gets into that state, it might
approach the point where *all* memory-resident processes die. In this
case, telnet/ftp/email/ssh/mysql/apache can all disappear, leaving you
with a box which pings quite happily but just won't let you in. Or give
any information out - the only solution is a reboot.

I'm afraid my only real suggestion (and I'm not a salesperson, before
anyone says so!) is to put more RAM in the box or upgrade to a bigger one.
A workaround is to ensure that as much real memory as possible is
available to running processes - ditch anything you don't need. If you're
not running any MySQL databases but it's installed, disable it (for
example). And in line with the Apache tuning notes which Zeffie posted,
ensure that you don't have too many child processes running - they will
consume RAM like there's no tomorrow.

I have seen customers here who add a single popular site to a RaQ which
then exhibits these exact symptoms. In all cases, moving the site to a
less heavily loaded or higher spec system has cured the problem - until
the site becomes too popular again...

HTH

Graeme

-- 
Graeme Fowler
WebFusion Internet Solutions
http://www.webfusion.co.uk