Spool Cascading is a Highwinds Software innovation that allows a provider to use
Tornado Back End in such a way as to store older articles on one server or
set of servers and newer articles on one server or a set of servers without the
need for duplication between the two sets. Before Spool Cascading, long retention
servers needed to carry the most recent X days along with any short retention servers
as well as all the articles older than X days. Now, a long retention server need
only carry articles older than X days and the Tornado system will aggregate all
the articles for the client to see.