On Thu, Feb 07, 2008 at 11:46:36AM -0500, Matt Pitts wrote:
> I just got advise from mst to not use mod_fcgid in production because it
> doesn't support external fastcgi and this is the way to do HA apps. I
> wanted to ask some questions and hear some arguments. I know there's
> some existing traffic on the list about this, but I thought some fresh
> info would be nice.
>
> We're currently running a Cat app under mod_fcgid in production that
> handles about a million hits a day b/t Cat and static files.
>
> Why did we chose mod_fcgid? Well, I tried playing around with
> mod_fastcgi for awhile and had problems getting the config straight -
> admittedly due to a lack of knowledge on my part. Then I read some
> tidbits about mod_fcgid being "better", so I tried it out and it "just
> worked" and has been "just working" ever since.
>
> Why is it so much better to have fastcgi as an external process? Is it
> because this is the only way to realistically to PAR-based deployments?
>
> What's wrong with having mod_fcgid do its process management.
Because then you restart the FastCGI processes when you restart the web
server.
With external, you can have
- webserver
- fastcgi for app version N
- fastcgi for app version N+1
all managed separately.
that means you can update by
- start N+1
- change apache config to point to N+1
- apachectl graceful
- stop N
which allows you to update with zero downtime - without even dropping a
single request on the floor.
And if something goes wrong, you can perform the process in reverse just as
easily.
I consider this essential for heavily-used applications since having a 5+
second window of "mid-upgrade" when the app doesn't respond is a pain in
the ass for users.
For less heavily used applications I don't care - apache starts the fastcgi
handlers for shadowcat.co.uk because it's mostly a news + brochureware
type site so a few seconds' downtime every so often really just doesn't
matter to us.
--
Matt S Trout Need help with your Catalyst or DBIx::Class project?
Technical Director http://www.shadowcat.co.uk/catalyst/
Shadowcat Systems Ltd. Want a managed development or deployment platform?
http://chainsawblues.vox.com/ http://www.shadowcat.co.uk/servers/
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