On 10/28/2014 1:48 AM, Modassar Ather wrote: > These Solrcloud instances are 8-core machines with a RAM of 24 GB each > assigned to tomcat. The Indexer machine starts with -Xmx16g. > All these machines are connected to the same switch.
If you have not tuned your garbage collection, a 16GB heap will be enough to create garbage collection pauses that are long enough to exceed a 15 second zkClientTimeout, which is the setting that is commonly seen in example configs. I was seeing pauses longer than 12 seconds with ConcurrentMarkSweep enabled on an 8GB heap, before I tuned the GC. With a 16GB heap, it would even be possible to exceed a 30 second timeout, which is the default in later releases. After I tuned the CMS collector, my GC pauses are no longer long enough to cause problems. These are GC settings that have worked for me and for others: http://wiki.apache.org/solr/ShawnHeisey#GC_Tuning Thanks, Shawn
