Common Issues with RMI Replication
Tomcat on Windows
Any RMI listener will fail to start on Tomcat, if the installation path has spaces in it. Because the default on Windows is to install Tomcat in "Program Files", this issue will occur by default. The workaround is to remove the spaces in your Tomcat installation path.
Multicast Blocking
The automatic peer discovery process relies on multicast. Multicast can be blocked by routers. Virtualisation technologies like Xen and VMWare may be blocking multicast. If so enable it. You may also need to turn it on in the configuration for your network interface card. An easy way to tell if your multicast is getting through is to use the Ehcache remote debugger and watch for the heartbeat packets to arrive.
Multicast Not Propagating Far Enough or Propagating Too Far
You can control how far the multicast packets propagate by setting the badly misnamed time to live. Using the multicast IP protocol, the timeToLive value indicates the scope or range in which a packet may be forwarded.
By convention:
0 is restricted to the same host
1 is restricted to the same subnet
32 is restricted to the same site
64 is restricted to the same region
128 is restricted to the same continent
255 is unrestricted
The default value in Java is 1, which propagates to the same subnet. Change the timeToLive property to restrict or expand propagation.
|