- Transactional Activation
- Sticky Sessions (think PUR module) More things to back up
- etc Etc.
On the other hand, clustering introduces some problems:
- If you use PostgreSQL, the journal can grow to the point it shuts down the DB server
- it It introduces a single point of failure
- you You can't do a rolling update if you only have one DB
- does Does not scale - a good rule of thumb seems to be: one DB connection per JCR workspace is open. In an OOTB configuration, there are about 30 JCR workspaces. If we're above, say, 4 publics, we actually have too many simultaneous DB connections.
- each Each cluster node needs its own (private) file system and search index.
A potential solution for all these issues is [Amazon Aurora].
A potential solution to the single point of failure problem is: create a redundant, second Jackrabbit cluster to avoid single point of failure in the content store.