On Wed, Mar 31, 2010 at 11:34 AM, Burton-West, Tom <tburt...@umich.edu> wrote: > Hello all, > > We have been running a configuration in production with 3 solr instances > under one tomcat with 16GB allocated to the JVM. (java -Xmx16384m > -Xms16384m) I just noticed the warning in the LucidWorks Certified > Distribution Reference Guide that warns against using more than 2GB (see > below). > Are other people using systems with over 2GB allocated to the JVM?
Plenty of people. People always want specific numbers for the general case (how many documents, how large a heap, etc)... and those specific numbers are always wrong for a good percent of the population and their specific setups and needs :-) In general, you don't want your heap larger than it needs to be - this leaves more free RAM for the OS to cache important parts of the lucene index files. > What steps can we take to determine if performance is being adversely > affected by the large heap size? If your query response latencies are acceptable, I wouldn't worry about it. If they normally are, but sometimes aren't, then GC could be the issue. One way to investigate further is to use the -verbose:gc and -XX:-PrintGC* options: http://java.sun.com/javase/technologies/hotspot/vmoptions.jsp -Yonik http://www.lucidimagination.com
