On 9/9/2014 8:46 AM, Salman Akram wrote: > You mean 3 'data centers' or 'nodes'? I am thinking if we have 2 nodes on > primary and 1 in secondary and we normally keep the secondary down would > that work? Basically secondary network is just for redundancy and won't be > as fast so normally we won't like to shift traffic there. > > So can we just have nodes for redundancy and NOT load balancing i.e. it has > 3 nodes but update is only on one of them? Similarly for the slave replicas > can we limit the searches to a certain slave or it will be auto balanced? > > Also apart from SOLR cloud is it possible to have multiple master in SOLR > or a good guide to upgrade a slave to master?
You must have three zookeeper nodes for a redundant setup. If you only have two data centers, then you must put at least two of those nodes in one data center. If the data center with two zookeeper nodes goes down, zookeeper cannot function, which means SolrCloud will not work correctly. There is no way to maintain SolrCloud redundancy with only two data centers. You might think to add a fourth ZK node and split them between the data centers ... except that in that situation, at least three nodes must be functional. Two out of four nodes is not enough. A minimal fault-tolerant SolrCloud install is three physical machines. Two of them run ZK and Solr, one of them runs ZK only. If you don't use SolrCloud, then you have two choices to switch masters: 1) Change the replication config to redefine the master and reload the core or restart Solr. 2) Write scripts that manually use the replication HTTP API to do all your replication, rather than let Solr handle it automatically. You can choose the master for every replication with HTTP calls. https://wiki.apache.org/solr/SolrReplication#HTTP_API Thanks, Shawn
