Maybe your Solr Document cache is big and that's consuming a big part of that JVM heap? If you want to be able to run with a smaller heap, consider making your caches smaller.
Otis ---- Sematext :: http://sematext.com/ :: Solr - Lucene - Nutch Lucene ecosystem search :: http://search-lucene.com/ >________________________________ >From: Sujatha Arun <suja.a...@gmail.com> >To: solr-user@lucene.apache.org >Sent: Tuesday, October 18, 2011 12:53 AM >Subject: Re: OS Cache - Solr > >Hello Jan, > >Thanks for your response and clarification. > >We are monitoring the JVM cache utilization and we are currently using about >18 GB of the 20 GB assigned to JVM. Out total index size being abt 14GB > >Regards >Sujatha > >On Tue, Oct 18, 2011 at 1:19 AM, Jan Høydahl <jan....@cominvent.com> wrote: > >> 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 >> >> > > >
