[Seaside] Call for help: Seaside performances

[Ramon Leon]

> > Avi, I heard you use Seaside to server dabbledb.com. Could 
> you provide 
> > some hints on the architecture for achieving good performances ?
> 
> The main hint I have is this: a large number of Squeak VMs 
> each handling a small number of sessions scales much better 
> than a large number of sessions on a single or small number 
> of Squeak VMs.
> 
> Cheers,
> Avi

I'm hosting http://www.reservetravel.com/v6 on a 3 server farm with each
server running one image on Windows Server 2003.  I'm running into
scalability issues when clients try and do a pay per click campaign and
Yahoo crawls me for 10000 keywords way too fast, each one starting a new
session, all hitting the same image because of a bug in our F5.  

To keep the site up, I have a script running every minute which will restart
the image if it fails to respond within an appropriate amount of time.  The
F5 brings it in and out of the pool as it goes up or down.  It sends me an
email when it does so, only happened a handful of times in the past few
weeks, not too bad.

Part of the problem is a bug in our BigIP F5 not load balancing correctly,
I'm waiting for the upgrade, but part of it does seem related to too many
sessions on an image.  I'm coming to the conclusion that I need to run
several images on a box as you're saying here.

Avi, any chance you can elaborate with some detail on what it takes to
dynamically bring up and take down images as necessary to handle the load?
Also, when using so many images, how does one manage keeping them all up to
date with the latest code?  Do you just have the images upgrade to the
latest version of a package on startup?  I know you're using Apache to fire
off some Ruby scripts to kick up the image, but knowing and doing are two
different things.  How do you have Apache dynamically proxy to a dynamic
port and make squeak start up on that port?  Any help in establishing some
best practices for production deployments would be benificial to many I'm
sure.

Ramon Leon
http://onsmalltalk.com