Bin,

This is going to depend on which route you go: clustering, clustering with
replication, or fail over.

CLUSTERING WITH REPLICATION

We have been struggling to get a clustering with replication environment
setup using the JBoss Cache solution (JbossCacheTicketRegistry), which was
outlined in the link you mentioned.  However, there have been some
unexpected problems maintaining a stable JBoss Cache replication cluster.
Though it is maintained by JA-SIG, there aren¹t many people you will find
that are very experienced with it much less managing JBoss Cache; there are
a number of people who will probably agree with me on that.  Another option
for doing clustering with replication is to use the MemCacheTicketRegistry
available in CAS 3.3.0.  This is the option favored by Rutgers, who is the
primary maintainer of the CAS code base.  Scott B can testify about it being
lightweight, however I don¹t know anyone else that has deployed it in their
environments.

CLUSTERING WITHOUT REPLICATION

If you want plain clustering without replication, then you could either go
with a backend data store holding users SSO information and have the CAS
servers be dummies by using the JpaTicketRegistry.  This would allow your
users to hit any of the CAS servers and remove the need for replicating
data, however you would have a single point of failure (data store).

FAIL OVER

However, most CAS deployments appear to use a active/passive fail over setup
where you have two deployments and have your load balancer direct traffic to
the primary and fail over to the secondary when necessary.  This option
requires little / no major customization.

NOTE: All of these options require you to configure the cookie generators to
set CAS cookies for a domain reachable by all machines within your cluster /
fail over environment.

HTH,
A-


On 10/10/08 12:01 AM, "Bin Rong" <[EMAIL PROTECTED]> wrote:

> Hi all, 
> 
> I am a newbie to CAS, and in our production environment, we have two apahche
> servers running behind a hardware load balancer, using ajp to balance
> out to several tomcat instances. Sticky session is used, and only one of the
> backend tomcat is used for CAS.
> 
> Now we want to load balance/failover CAS, the options are:
> 
> 1. Clustering CAS
> 2. Have database-backed registry, so that multiple CAS can validate the ticket
> vended by other CAS servers.
> 
> Just wondering what is the best practise?
> 
> We think the database-backed is a good one, and I've searched the web, there
> is very little information in this regard, except
> http://www.ja-sig.org/wiki/display/CASUM/Clustering+CAS. Could anyone point to
> any source of information or any detailed howto guide?
> 
> Any advise is appreciated.
>  
> Bin
> 
> 
> _______________________________________________
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> [email protected]
> http://tp.its.yale.edu/mailman/listinfo/cas

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