This solution has the advantage that none of the core Jive code would need to be changed. It has the disadvantage that posting would break if the single posting server died. To accomplish this method, you'd simply modify your forum skin to explicitly point to a single server for posting. An upcoming version of Jive will switch to a new unique ID generation scheme. This can lead to problems when using multiple app servers since cache expiration cannot happen across app servers during object deletions.
Deletion is a relatively infrequent activity so perhaps caching problems can essentially be ignored.
However, those wishing to ensure maximum data integrity should consider the issue. This preserves the performance benefit of caching but also guarantees data integrity. This will probably be the method of choice for the future, scalable version of Jive. Disable all caching. This will increase the load on the database, but guarantees data integrity.