title: replicated HSQLDB
body: <p>We're reviewing different DB engines to be used in our spring java project (actually grails project). Neither of <code>real DB</code> <code>MySQL/PostgreSQL</code> support clustering out of the box (it's still possbile to cluster DB instances using 3rd party software). 
  I'm thinking of using <code>HSQLDB</code> locally on each server and replicate them using <code>HSQLDB-R</code> (via <code>JGroups</code>). The size of every database won't exceed few hudnreds of megabytes. 
  Could someone tell me what hidden problems I should expect? </p>