The Underscore Archives

On 12/4/06, Dominic Mitchell <dom at happygiraffe.net> wrote:

> On Mon, Dec 04, 2006 at 01:05:01PM +0000, Jay Caines-Gooby wrote:
> > My current webserver setup is Debian Sarge with Apache2 and Ruby & PHP
> > both run from FastCGI.
> >
> > The main box is crashing on a random basis and I'm now ready to point
> > the finger at Apache2 + FastCGI, which anecdotally is known to be
> > "unstable at times".
>
> What does "crashing" actually mean?  Apache dieing? some bits not
> responding?

Kernel death and/or whole networking stack :-/

Sometimes the box reboots othertimes I have to use my remote re-boot
capability as I can't ssh in. :P

> James Duncan Davidson has been through similar troubles and explained
> them quite well.
>
>     "Deploying Rails with LightTPD"
>     http://blog.duncandavidson.com/2005/12/deploying_rails.html
>     "Real Lessons for Rails Deployment"
>     http://duncandavidson.com/essay/2005/12/railsdeployment
>     "Virtual Hosting Rails Applications with LightTPD"
>     http://blog.duncandavidson.com/2006/01/virtual_hosting.html
>     "Deploying Rails with Apache 2"
>     http://blog.duncandavidson.com/2006/01/deploying_rails.html
>     "Rails on Apache with mod_fcgid"
>     http://blog.duncandavidson.com/2006/02/rails_on_apache.html
>     "The Web Is a Pipe"
>     http://blog.duncandavidson.com/2006/06/the_web_is_a_pi.html
>
> The last one is most worthwhile reading, I reckon...

Ah. Thanks for these.

> I don't have experience with any of this at any professional level, just
> the rails app I use for my blog (typo).  I run Apache 2.2.3 and rails
> 1.1.6, along with some PHP (mostly just for squirrelmail).  I was
> getting very fed up with FastCGI as I would get random failures between
> Apache and the backend rails processes a lot.  I wasn't able to
> successfully diagnose these, in large part thanks to the utterly opaque
> nature of FastCGI.
>
> So I switched to mongrel and haven't looked back.  I run mongrel on a
> high port and use mod_proxy to forward traffic to it.  I've had no
> troubles with it at all.  However, this isn't a performant setup.
> Because rails under mongrel is single threaded, you really need to run
> mongrel_cluster to run several instance of mongrel at a time, and
> use Apache's mod_proxy_balancer to load balance between them.  Or at
> least, that's what I've heard.

Yeah, that's what the Codahale post covers. I'm working through it at the mo.

>     http://blog.innerewut.de/articles/2006/04/21/scaling-rails-with-apache-2-2-mod_proxy_balancer-and-mongrel
>     http://httpd.apache.org/docs/2.2/mod/mod_proxy_balancer.html
>
> Good luck getting it all sorted.
> -Dom
>
> P.S. Thanks for the snipperoo t-shirt -- wearing it now!

Photos!

Some good links there, thanks Dom. Also I've just stumbled over
multi-master circular mysql replication and the magic
auto_increment_increment and auto_increment_offset variables. Sweet!
I've been scratching my head about replication between the two
data-centres and this nails it :)

--
Jay Caines-Gooby
jay at gooby.org
+44 (0)7956 182625
skype:jaygooby
http://snipperoo.com
http://blog.snipperoo.com