[Deploying Sakai] Deployment sizing question

[Todd Williams]

Hey folks,

I'm a sys admin with the University of Florida and we're in the early 
stages of planning the replacement of our Webct Vista system with Sakai 
over the coming year.  I've been tasked with collecting deployment 
information from other institutions that have implemented Sakai as their 
primary/sole LMS.

Specifically I'm interested in information that will help me develop 
initial sizing recommendations in terms of hardware/software platform 
for an institution of our size.  Just as a starting point UF frequently 
has 1500 concurrent LMS user logins throughout the day.  We have ~45000 
traditional students in addition to a fairly large number of 
non-traditional distance education students.

Coming from our current WebCT installation our preferred deployment 
environment will be Linux and Oracle.  Via other projects my group has a 
solid understanding of Apache/Tomcat as well.  So the underlying pieces 
are familiar, but what isn't obvious is the sizing for our Sakai 
deployment.  For WebCT we've been running with 6 application nodes and a 
single, beefy Oracle 9i server.  After looking at the list of 
deployments that the Sakai Foundation recommended(1), I see a number of 
institutions of similar size using infrastructure similar to what we 
want to do- this is encouraging.  However, I still have a handful of 
questions, so here goes:

What methods and metrics are people using to asses how many application 
servers will be necessary?

What network load balancers are being used to distribute load across 
their application clusters?

What methods are being used for node affinity within the load balancer? 
  ie. stickytimes, cbr/cookie persistence, something else?

Has anyone implemented Oracle RAC in support of their Sakai system?

Has Oracle 11g been successfully implemented as the backend for Sakai?

For what it's worth, given our desired implementation timeline it looks 
like our pilot rollout and eventual full production rollout will be with 
Sakai 3 (assuming the predicted release dates for RC and final Sakai 3 
hold up).  I only mention that for consideration in case the move the 
version 3 will affect any of the underlying components in the support 
matrix.

Thanks in advance for any information you can provide that will help in 
my endeavor.  I'm excited about moving to Sakai, and I look forward to 
working with the community.

Cheers!
-- 
Todd Williams
tcwill at ufl.edu
CNS Open Systems
University of Florida


(1)http://jira.sakaiproject.org/jira/secure/IssueNavigator.jspa?pager/start=0