Without contesting the good points. I would say memory is cheap. For an application i worked on, we had about 6 different applications sitting on two 4 by 16 machines. The -xmx arguments of all apps put together came up to about 10 gigs RAM and the rest was left open. i dont think serious application owners care about money sunk on hardware.
Further, I agree that caching requires an overhead in terms of keeping various clusters in synch or managing updates etc.. but clients can be kept transparent of all this. there may be a period of a few 100 milliseconds to upto a couple of seconds when clients may get dirty reads if the cache design allows it - but that could be a small price to pay over the general speed of cache access. Anyways - sorry for contributing to making this a totally non-struts topic! On Tue, 15 Feb 2005 11:03:01 -0500, Bill Schneider <[EMAIL PROTECTED]> wrote: > >> how do you manage cross container caches if you are clustered - when > >> you are using static members on classes? How do guarantee sameness on > >> different physical machines? We do have a few caches in our > >> application and are facing issues due to this design or an improperly > >> implemented version of this design. > > Also, be aware that caching can actually degrade application performance > in some cases. Everything you cache takes space in the JVM heap, > reducing what's left to process active requests. So it's possible to > lose more cycles in GC than you saved by caching in the first place. You > can just keep increasing -Xmx, but that can hurt you if the JVM starts > using swap space/virtual memory for the Java heap. > > If you're using a clustered cache, you also have the overhead of keeping > the caches on each JVM in sync. That adds network as well as processing > overhead for marshalling and unmarshalling cached objects. > > In summary, J2EE webapp performance involves a lot of tradeoffs. Caching > is important but has to be used judiciously to be beneficial. > > -- Bill > -- > Bill Schneider > Chief Architect > > Vecna Technologies > 5004 Lehigh Rd., Suite B > College Park, MD 20740 > [EMAIL PROTECTED] > t: 301-864-7253 x1140 > f: 301-699-3180 > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
