Clustering JNDI

Question

Hi,
As I'm using clustering of weblogic 7.0, and I know I cannot use ServletContext
for placing objects as it's not replicated via all the servers, I wondered if
I could use Context for that.
If I place objects in the JNDI Context using bind, and I update them using rebind,
will those object and changes be clustered to every node? What should I do for
changes to be propagated?
Does the server's perfomance suffer too much from changing use of JNDI instead
of ServletContext?
Is there any problem for concurrent access to objects in JNDI Context?
I know there's a product called Coherence by Tangosol for using ServletContext
in clustered environments, but I cannot use it as my client does not wanna hear
about more products to be bought. :.-(
Thanks

Answer 1

"Ignacio Sanchez" <[email protected]> wrote in message news:<[email protected]>...
Thanks for your reply,
Anyway, I see one big problem, which is included in that page, in the warning.
Here it is: "Do not use the cluster-wide JNDI tree as a persistence or caching
mechanism for application data. Although WebLogic Server replicates a clustered
server instance's JNDI entries to other server instances in the cluster, those
entries are removed from the cluster if the original instance fails".
So, this does not seem to be the solution.
"SIPTech Community" <[email protected]> wrote:
"Ignacio Sanchez" <[email protected]> wrote:
Hi,
As I'm using clustering of weblogic 7.0, and I know I cannot use ServletContext
for placing objects as it's not replicated via all the servers, I wondered
if
I could use Context for that.
If I place objects in the JNDI Context using bind, and I update them
using rebind,
will those object and changes be clustered to every node? What should
I do for
changes to be propagated?
Does the server's perfomance suffer too much from changing use of JNDI
instead
of ServletContext?
Is there any problem for concurrent access to objects in JNDI Context?
I know there's a product called Coherence by Tangosol for using ServletContext
in clustered environments, but I cannot use it as my client does not
wanna hear
about more products to be bought. :.-(
ThanksHi,
Every server instance in a cluster maintains Clusterwide JNDI Tree
(for clustered
objects).
Binded objects in any cluster server instance will be replicated
in other
server instances just after successful
binding.
Pls. view this URL for more details :
http://edocs.bea.com/wls/docs70/cluster/features.html#1007508
Prema
Many Application Servers make use of caching for the JNDI Tree when
you have more than 1 clone (vertical or horizontal).
If you make use of JNDI in order to store "constant" information, you
need to use just bind /rebind and lookup... but if you want update
frequently a JNDI object you will have to clean this cache by setting
the appropriate property in the JNDI Environment... because you could
experience a dirty (old) value by making a simple lookup.
A sample using IBM WebSphere:
public static final Object lookupEnvEntry(InitialContext ic, String
entryName, boolean clearCache) {
     try {
          if (clearCache) {
               Hashtable env = ic.getEnvironment();
               env.put("com.ibm.websphere.naming.jndicache.cacheobject",
"cleared");
               ic = new InitialContext(env);
          return (String)ic.lookup(entryName.trim());
     } catch (Exception ex) {
          System.out.println("Initial Context: Error retrieving Environment
Entry: " + entryName.trim() + " - " + ex.getMessage());
          return null;