> We are considering a JASIG CAS implementation but can’t seem to find any > server specs or supported OSs. We are considering implementing on Red Hat > AS. From your experience, what would be a sufficient machine for 6,000+ plus > users on 12 or so applications?
A better way to think about capacity planning is to consider the number of authenications per second and the number of tickets issued per second. If those 6000+ users are expected to authenticate once per day, say at the start of the day, you can estimate authentications/sec as 6000/(3600 * 24) which is a very small number that can almost certainly be met by most enterprise hardware and systems. The bottleneck in authentication is the underlying authentication store, so you should spend any energy on optimization at that point. For example, LDAP connection pooling is a best practice if you're authentication against a directory. Issuing tickets to access services is a relatively lightweight operation. You can estimate the tickets/sec by considering the average number of services that a user will access in an SSO session. A worst case estimate where all users access all services is 6000*12/(3600 * 24), again assuming that an SSO session lasts a whole day. Again, that's a very low number and can likely be handled by any competent hardware and ticket storage mechanism. Of course the estimates above are averages and the actual instantaneous values may be much higher due to natural cycles. For example, CAS authentications may spike in the 10 minutes around class start times due to students logging into a CAS-enabled learning management system. (We see this general pattern.) The patterns you observe may be different, and the only way to be prepared for them is to perform load testing in a test environment. I encourage you to review the JMeter test plans on the wiki [1] and consider load testing; I'm hopeful you'll find the barrier to load testing is fairly low relative to the value of data it produces. M [1] https://wiki.jasig.org/display/CASUM/Apache+JMeter -- You are currently subscribed to [email protected] as: [email protected] To unsubscribe, change settings or access archives, see http://www.ja-sig.org/wiki/display/JSG/cas-user
