Lemme try with a 'from' address that will be accepted. -- Dan Christopherson (danch) nVisia Technical Architect (www.nvisia.com) Opinions expressed are mine and do not neccessarily reflect any position or opinion of nVISIA. --------------------------------------------------------------------------- If you're a capitalist and you have the best goods and they're free, you don't have to proselytize, you just have to wait. -Eben Moglen ---------- Forwarded message ---------- Date: Thu, 22 Feb 2001 16:56:28 -0600 (CST) From: Dan Christopherson <[EMAIL PROTECTED]> To: JBoss-Dev <[EMAIL PROTECTED]> Subject: Re: [jBoss-Dev] Article on clustering On Thu, 22 Feb 2001, Dan OConnor wrote: > Hey Rickard, > > Thanks for the pointer to the article. > > Did you notice how it describes how an entity bean might get > "pinned" against a single server in the cluster? Did you understand > this? It didn't make a whole lot of sense to me. The entity would be constrained to existing on one and only one server in the cluster. > > A clustered entity would use commit option "C", right? Not if they're pinned. > So the > claim that it would be too expensive to have multiple copies of the > same entity seemed obviously false. It depends on how the vendor you work for implemented clustering 8^}). It also depends on which 'expense' you're optimising for - network traffic for cache coherency (if you allow commit option <> C, but no pinning), database accesses (if you force commit option C), memory use, container developer time... > However, I can envision many > scenarios where a stateful session bean might get pinned to a > server. That makes good sense, although then you wouldn't be able to fail-over. > Do you think this is what he was reaching for? Or was he > referring to some strange clustered commit option "A" scenario, or > maybe a client-managed transaction? I think 'Strange commit option A scenario' is what he was thinking. I think allowing commit option A for entities leads to complexity no matter how you implement it - cache coherency or pinning. That (and stateful sessions) is where clustering gets fun - I was kind of dissappointed that the guy spent his time doing the hand-wave thing about how you do the location bit and never got to this meaty bit. > > -Dan > > On 22 Feb 01, at 13:43, Rickard �berg wrote: > > > Hey > > > > You may want to read this: > > http://www.onjava.com/pub/a/onjava/2000/12/15/ejb_clustering.html > > > > regards, > > Rickard > > > > -- > > Rickard �berg > > > > Email: [EMAIL PROTECTED] > > > > > -- Dan Christopherson (danch) nVisia Technical Architect (www.nvisia.com) Opinions expressed are mine and do not neccessarily reflect any position or opinion of nVISIA. --------------------------------------------------------------------------- If you're a capitalist and you have the best goods and they're free, you don't have to proselytize, you just have to wait. -Eben Moglen
