Better single machine or cluster?

[mglowacki]

hi,

     I would like to get your opinion. I have web application with EJB3 usage which is getting more and more visitors. I need to start thinking about upgrading the hardware. Currently it's 2 machines, one for Apache + JBoss 5.1, 8 cores 2,4GHz with 16GB RAM and execatly same for Postgres 9. Both working as virtual machines.

     Now, my question is, what is better, buy a better machine, like with 16 or 32 cores for JBoss, or better to create one more virtual machine and create cluster? When I review logs I see a some blocked threads waiting for various resources and I got the feeling, that increasing CPUs can grow that bigger and performance gain will not be as expected.

     What you think?

Regards,

Michal

[wdfink]

IT depend extremely on the application programming.

If only the threads (CPU power) is the issue increase the HW speed.

But often it is a mixture.

You should analyze why the threads are blocked, maybe increasing the DB connection might help.

Also the GC of the JVM might be a problem, in this case a split in deparate cluster instances are helpful.

So analyze it well, otherwise a optimization is a game of change

If you have special questions fell free to ask, your welcome.