On 9/18/2013 8:12 AM, Indika Tantrigoda wrote: > I am using 3 Solr instances behind an Amazon ELB with 1 shared. Serving > data via Solr works as expected, however I noticed a few times a 503 error > was poping up from the applications accessing Solr. Accessing Solr is done > via the AWS ELB. > > 3 Zookeeper instances also run on the same instances as Solr on a separate > disk. > > Solr version is 4.4. > > This issue seems to be a sporadic issue. Has anyone else observed this kind > of behavior ?
What kind of session timeouts have you configured on the amazon load balancer? I've never used amazon services, but hopefully this is configurable. If the timeout is low enough, it could be just that the request is taking longer than that to execute. You may need to increase that timeout. Aside from general performance issues, one thing that can cause long request times is stop-the-world Java garbage collections. This can be a sign that your heap is too small, too large, or that your garbage collection hasn't been properly tuned. http://wiki.apache.org/solr/SolrPerformanceProblems#GC_pause_problems http://wiki.apache.org/solr/SolrPerformanceProblems#How_much_heap_space_do_I_need.3F That same wiki page has another section about the OS disk cache. Not having enough memory for this is the cause of a lot of performance issues: http://wiki.apache.org/solr/SolrPerformanceProblems#OS_Disk_Cache Thanks, Shawn
