Hi Sujatha, Are you sure you need 20Gb for Tomcat? Have you profiled using JConsole or similar? Try with 15Gb and see how it goes. The reason why this is beneficial is that you WANT your OS to have available memory for disk caching. If you have 17Gb free after starting Solr, your OS will be able to cache all index files in memory and you get very high search performance. With your current settings, there is only 12Gb free for both caching the index and for your MySql activities. Chances are that when you backup MySql, the cached part of your Solr index gets flushed from disk caches and need to be re-cached later.
How to interpret memory stats vary between OSes, and seing 163Mb free may simply mean that your OS has used most RAM for various caches and paging, but will flush it once an application asks for more memory. Have you seen http://wiki.apache.org/solr/SolrPerformanceFactors ? You should also slim down your index maximally by setting stored=false and indexed=false wherever possible. I would also upgrade to a more current Solr version. -- Jan Høydahl, search solution architect Cominvent AS - www.cominvent.com Solr Training - www.solrtraining.com On 17. okt. 2011, at 19:51, Sujatha Arun wrote: > Hello > > I am trying to understand the OS cache utilization of Solr .Our server has > several solr instances on a server .The total combined Index size of all > instances is abt 14 Gb and the size of the maximum single Index is abt 2.5 > GB . > > Our Server has Quad processor with 32 GB RAM .Out of which 20 GB has been > assigned to JVM. We are running solr1.3 on tomcat 5.5 and Java 1.6 > > Our current Statistics indicate that solr uses 18-19 GB of 20 GB RAM > assigned to JVM .However the Free physical seems to remain constant as > below. > Free physical memory = 163 Mb > Total physical memory = 32,232 Mb, > > The server also serves as a backup server for Mysql where the application DB > is backed up and restored .During this activity we see that lot of queries > that nearly take even 10+ minutes to execute .But other wise > maximum query time is less than 1-2 secs > > The physical memory that is free seems to be constant . Why is this constant > and how this will be used between the Mysql backup and solr while > backup activity is happening How much free physical memory should be > available to OS given out stats.? > > Any pointers would be helpful. > > Regards > Sujatha
