This problem surfaced in Solr 4.x where the state is kept in a single "clusterstate.json" file.
Work is underway to try and improve this situation. These problems are due to how SolrCloud updates cluster state in ZooKeeper in response to cluster changes. Try to keep the number of collections as low as possible. With thousands of collections, any little problem or change to the cluster can cause a stability death spiral that may not recover for tens of minutes. Regardless of the number of nodes or available resources, SolrCloud begins to have stability problems when the number of collections reaches the low hundreds. The Java heap is discussed in a later section of this page. It is very easy to build an index that will not function at all if the heap cannot be made larger than 2GB.
#FONTS COLLECTION ON DISK SOFTWARE#
There's nothing wrong with 32-bit software or hardware, but a 32-bit Java is limited to a 2GB heap. A 64-bit Java requires a 64-bit operating system, and a 64-bit operating system requires a 64-bit CPU. It is strongly recommended that Solr runs on a 64-bit Java. For standalone Solr instances or when using SolrCloud with clients that are not cloud-aware, multiple replicas might require a load balancer. If more query scalability is required, eventually that won't be enough, and you will need to add multiple replicas of your index on multiple machines (preferably separate physical hardware) to scale further. Adding memory can sometimes let Solr handle a higher rate. Solr requires sufficient memory for two separate things: One is the Java heap, the other is "free" memory for the OS disk cache.Īnother potential source of problems is a very high query rate. The rest of this document outside of this one paragraph is not specific to ANY version of Solr.Ī major driving factor for Solr performance is RAM. This is highly version specific, so if you are not running one of the affected versions, don't worry about it. There is a performance bug that makes *everything* slow in versions 6.4.0 and 6.4.1.