Ok. Full GC Pauses can slow-down the application. We would surely tune the GC also.
What is the difference between the network traffic that a typical cluster( App. server like weblogic ) generates to replicate sessions and the network traffic that memcached servers generate to sync. up ? We have switched off WebSphere session replication to reduce this traffic ? I am just looking for details to convince the team to look at memcached. Switching off session replication is a good reason. Mohan On Thu, Apr 30, 2009 at 11:59 AM, Chris Lamprecht <[email protected]> wrote: > The problem with large Java heaps and long-lived objects (such as cached > objects), is GC pauses can stop the world for long periods of time. In > fact, this is what made us look at memcached in the first place -- to > replace our simple HashMap-based cache. Java's GC is always improving, but > memcached works in O(1) time today. > Not to mention memcached's nice distributed cache possibilities. > > -chris > > > On Thu, Apr 30, 2009 at 1:19 AM, Mohan Radhakrishnan > <[email protected]> wrote: >> >> Hi, >> I have a basic question. We are planning to buy expensive >> hardware like HP-UX or IBM-AIX or Windows. The processors are 64-bit. >> I checked the JVM heap limitations and found that upto 4GB is >> supported. >> >> I also know that memcached cache farms can scale better than the >> Java heap. What is the deciding factor here ? Can't the java heap( 2 >> cluster members ) itself be used as a cache ? I know that in a web >> application we are limited to some type of scope like the session for >> caching. >> >> How would I go about evaluating our requirements to support a large >> number of users( 300000) ? >> >> >> Thanks, >> Mohan > >
