I'm trying to get a sample cluster of tomcat servers (server A, B and C) to use
a distributed cache. The ‘hello’ cache is configured on each server with a
different TcpListenerPort on each server (8020, 8021, 8022) like this:
jcs.region.hello=LTCP
…
jcs.auxiliary.LTCP=org.apache.commons.jcs.auxiliary.lateral.socket.tcp.LateralTCPCacheFactory
jcs.auxiliary.LTCP.attributes=org.apache.commons.jcs.auxiliary.lateral.socket.tcp.TCPLateralCacheAttributes
jcs.auxiliary.LTCP.attributes.UdpDiscoveryEnabled=false
jcs.auxiliary.LTCP.attributes.AllowGet=true
jcs.auxiliary.LTCP.attributes.Receive=true
jcs.auxiliary.LTCP.attributes.TcpListenerPort=8020
jcs.auxiliary.LTCP.attributes.TcpServers=localhost:8020,localhost:8021,localhost:8022
Server A has a page that sets a value in the cache like this:
cache = JCS.getInstance("hello");
cache.put(“message", “Hello from server A");
Server B, and C try to get the value without setting it:
cache = JCS.getInstance("hello");
add(new Label("message", "Server B -> cache has : " +
cache.get(“message");));
The first time I access the page on server A I get an exception - "Cannot
connect to localhost:8021”. If I access the page on each server then things
appear to start communicating; however, the “message” entry from the “hello”
region is set on server A and null on B and C. Sometimes I see the value on
server C displayed properly but never on server B.
With a configuration like this should I expect to see values immediately
distributed to the other servers?
Is there a way I should be bootstrapping the cache when the server starts? If
the servers need to communicate with one another it would seem to me that they
need to be listening long before the first time the server tries to access the
cache.
For performance I would like to use the cache to store serialized XML data
instead of storing it in the session or a database. The data remains in the
cache while the user transforms it through several request cycles. So during a
request cycle the XML data would be retrieved, transformed, and stored back in
the cache. In a clustered environment I need the XML data available on every
server in the cluster. Is this an acceptable use case for JCS?
Thanks
