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I have a few ideas how to solve the problem, but one question about jboss clustering. Please, keep in mind these applications were written very poorly, that is why they require so much memory and there is nothing i can do about that right now.

So, I have clustered applications on Jboss where the application was small enough to run on one box. Meaning that one machine could handle the load. But, the current problem is that i have been asked to run several systems on the same environment.

Our machines are virtuals and due to limited hardware, are restricted to 8 GB RAM, which gives jboss about 7GB to itself. Unfortunately, that isn't enough to run the group of applications. Im constantly getting heap errors and crashes.

If i cluster 2 or 3 jboss instances together, can i run applications that consume more resources than a single box can handle?

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migrated from Sep 21 '12 at 18:50

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What OS are you running? If it is Windows 64 bit then I doubt your heap size is as big as you think it is. Multiple instances in a clustered or load balanced situation can work around this. – maple_shaft Sep 21 '12 at 18:45
im running suse on a 64 bit jvm on an iseries as/400 – scphantm Sep 21 '12 at 18:53
This is a performance tuning exercise and I'm afraid you're 'guessing'. You need to measure what resources are actaully being over stretched and tie that back to the root cause. Analyse your GC logs, check vmstat, run a profiler etc. Even if you could cluster, you'er only delaying the problem. – Martijn Verburg Sep 22 '12 at 11:07
Im aware of that, the only problem with your suggestions is the client hasn't decided if they want to even keep these applications or go to a new architecture. until that decision is made, there are to be no changes to the system. they don't want to put money in software that may be thrown away soon. – scphantm Sep 24 '12 at 16:50

No. It doesn't work that way. No cluster (outside of the research arena) can "lend" resources to another node. So nodes will always be limited to whatever they natively have (or less, you can chop a node into smaller pieces).

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ok, if thats the case is it possible for me to have two separate instances of jboss, each running different applications, but link Jaas and Jndi? what im trying to centralize are sessions and logins between the different applications. – scphantm Sep 21 '12 at 19:02
Good question, I don't know and unfortunately that'd be a question for Stack Overflow. Sorry that you keep getting redirected but these are pretty complex interactions. – Chris S Sep 21 '12 at 19:06

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