title: Quartz clustering not working
body: <p>I have my application under Jboss (database is informix) using quartz for scheduling purpose. 
  When I have quartz running on 2 clustered Jboss server, I see the jobs are firing on both the servers (few milliseconds apart) for the same fire time. </p>
  
  <p>Any pointers on what can be tweaked such that quartz can run correctly on clustered servers would be of great help. </p>
  
  <p>Thanks for your time and feedback. </p>
  
  <p>Below is how my quartz.properties look like: </p>
  
  <pre><code>org.quartz.scheduler.instanceName = MYQuartzScheduler 
  org.quartz.scheduler.instanceId = AUTO 
  
  org.quartz.threadPool.class = org.quartz.simpl.SimpleThreadPool 
  org.quartz.threadPool.threadCount = 5 
  org.quartz.threadPool.threadPriority = 5 
  
  org.quartz.jobStore.class = org.quartz.impl.jdbcjobstore.JobStoreTX 
  org.quartz.jobStore.driverDelegateClass = org.quartz.impl.jdbcjobstore.StdJDBCDelegate 
  org.quartz.jobStore.dataSource = myDS 
  org.quartz.jobStore.tablePrefix = quartz_ 
  org.quartz.jobStore.useProperties = false 
  org.quartz.jobStore.misfireThreshold = 60000 
  org.quartz.jobStore.maxMisfiresToHandleAtATime = 20 
  
  org.quartz.dataSource.myDS.jndiURL= xyzTX 
  
  org.quartz.jobStore.isClustered = true 
  org.quartz.jobStore.clusterCheckinInterval = 20000 
  
  org.quartz.plugin.jobInitializer.class = org.quartz.plugins.xml.JobInitializationPlugin 
  org.quartz.plugin.jobInitializer.fileNames=abc_jobs.xml 
  org.quartz.plugin.jobInitializer.overWriteExistingJobs = true 
  org.quartz.plugin.jobInitializer.failOnFileNotFound = true 
  org.quartz.plugin.jobInitializer.scanInterval = 60
  </code></pre>