Am 16.03.2012 16:42, schrieb Mike Austin:
It seems that the biggest real-world advantage is the ability to control core creation and replacement with no downtime. The negative would be the isolation however the are still somewhat isolated. What other benefits and common real-world situations would you use to talk me into switching to Solr cores?
Different Solr cores already are quite isolated: They use different configs, different caches, different readers, different handlers...
In fact, there is not much more common between Solr cores except the solr.xml configuration.
One additional advantage is that cores need less footprint in Tomcat than fully deployed Solr web applications.
I don't see a single drawback of multiples cores in contrast to multiple web apps....
...except one, but that has nothing to do with Solr, only with the JVM itself: If you have large hardware environment with lots of RAM, than it might be better to have multiple Tomcat instances running in different OS processes. The reason is Java's garbage collector that works better with not-so-huge memory.
Sometimes it might be even better to have two or four replicated Solr instances in different Tomcat processes than just one. You'll avoid longer stop-the-world pauses with Java's GC as well.
However, this depends on the environment and needs to be avaluated as well...
-Kuli
