[Deploying Sakai] Deployment sizing question

Stephen Marquard stephen.marquard at uct.ac.za
Thu May 14 05:12:43 PDT 2009

Hi Adi,

What in your view are the known and yet-to-be-determined reasons for Sakai going unresponsive - can you post some JIRA refs (or create new JIRAs if there are problems you're aware of that aren't in JIRA, no matter how sketchy)? What do the logs say when they're unresponsive?

Are you using dbcp or c3po for your connection pool? I also wonder if your appservers are really not memory-bound - what maximum full GC times do you see?


Stephen Marquard, Learning Technologies Co-ordinator
Centre for Educational Technology, University of Cape Town
Email/IM/XMPP: stephen.marquard at uct.ac.za 
Phone: +27-21-650-5037 Cell: +27-83-500-5290 

>>> "R.P. Aditya" <rpaditya at umich.edu> 2009/05/13 06:24 PM >>>
Hi Todd,

Here's how we (University of Michigan) deal with the issues you bring up:

In gmane.comp.cms.sakai.production, you wrote:
> What methods and metrics are people using to asses how many application 
> servers will be necessary?

we've found that appservers are not cpu bound, and now with 64-bit machines
and 6GB heaps are not memory bound -- for our load, we have 5 appservers and
they are overkill, though they are necessary to spread the risk of Sakai going
unresponsive (for many different known and yet-to-be-determined reasons)

you can see our load at:


let me know if you need more specifics

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

We use Netscalers

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

cookie persistence and backup with sourceip for clients that don't send
cookies (ie. Webdav)

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

we tried it in our development environment and determined it was more complex
than we wanted and it didn't buy us enough (we couldn't figure out transparent
jdbc failover with the oracle thin client)

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

we have successfully run our load-test environment against 11g and are
planning to upgrade to it in production this calendar year

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