[opencms-dev] Clustering Solutions

[Andrew Kerr]

Greetings,

We have been experiencing performance problems with OpenCMS under 
extremely heavy load.  As such, we thought we should investigate the 
possibility of clustering our OpenCMS server.

Unfortunately, perusal of this mailing list has made it clear that 
OpenCMS 5.0.1 does not support clustering.

We've been trying to think of other ways to get the benefits of 
clustering using OpenCMS as it stands today.  Our site consists of both 
statically exported content, as well as dynamic content that is served 
directly out of OpenCMS.  Here's what we're thinking:

1) Set up separate Apache/Tomcat/OpenCMS instances on two different 
machines.  The two instances will share a MySQL instance on a third machine.

2) Some sort of load balancer will distribute normal site visitors to 
the two sites.

3) All statically exported content will be published to a single 
document root that is shared between the two machines, via NFS, rsync, 
or some other synchronization mechanism.  This means that any newly 
published content that is statically exported will immediately be 
available to both servers.

4) Content management tasks will be performed only on one of the OpenCMS 
instances.  Let's call this the primary instance.

5) When a publish is performed, the primary instance will notify the 
secondary OpenCMS instance, which will then clear its Flex cache, so 
that users being served by the secondary instance will begin to see the 
freshly-published dynamic content.

We have a good handle on the first four items, but are unsure how we can 
accomplish the fifth item.  Here's what I'm thinking may be possible:

a) The secondary instance will have a JSP whose job is simply to clear 
the entire Flex cache.  Is there an API available to do this cache-clearing?

b) The primary instance will invoke this JSP when a publish event 
occurs.  Is there a hook in OpenCMS that we can use to detect publish 
events?

Any suggestions or help with this issue would be greatly appreciated.

Best regards,
Andrew Kerr