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The "SolrCloud" page has been changed by Mark Miller: http://wiki.apache.org/solr/SolrCloud?action=diff&rev1=43&rev2=44 == SolrCloud == - SolrCloud is the name of a set of new distributed capabilities in Solr. Passing parameters to enable these capabilities will enable you to set up a highly available, fault tolerant cluster of Solr servers. + SolrCloud is the name of a set of new distributed capabilities in Solr. Passing parameters to enable these capabilities will enable you to set up a highly available, fault tolerant cluster of Solr servers. Use SolrCloud when you want high scale, fault tolerant, distributed indexing and search capabilities. == Getting Started == Check out and build Solr trunk: https://svn.apache.org/repos/asf/lucene/dev/trunk and build the example server with {{{cd solr; ant example}}}. @@ -147, +147 @@ == ZooKeeper == Multiple Zookeeper servers running together for fault tolerance and high availability is called an ensemble. For production, it's recommended that you run an external zookeeper ensemble rather than having Solr run embedded servers. See the [[http://zookeeper.apache.org/|Apache ZooKeeper]] site for more information on downloading and running a zookeeper ensemble. More specifically, try [[http://zookeeper.apache.org/doc/r3.3.4/zookeeperStarted.html|Getting Started]] and [[http://zookeeper.apache.org/doc/r3.3.4/zookeeperAdmin.html|ZooKeeper Admin]]. It's actually pretty simple to get going. You can stick to having Solr run ZooKeeper, but keep in mind that a ZooKeeper cluster is not easily changed dynamically. Until further support is added to ZooKeeper, changes are best done with rolling restarts. Handling this in a separate process from Solr will usually be preferable. - In terms of trying to make sure ZooKeeper is setup to be very fast, keep a few things in mind: Solr does not use ZooKeeper intensively - optimization's are likely not necessary. Also, while adding more ZooKeeper nodes will help some with read performance, it will slightly hurt write performance. Again, Solr does not really do much with ZooKeeper when your cluster is in a steady state. + In terms of trying to make sure ZooKeeper is setup to be very fast, keep a few things in mind: Solr does not use ZooKeeper intensively - optimizations may not be necessary in many cases. Also, while adding more ZooKeeper nodes will help some with read performance, it will slightly hurt write performance. Again, Solr does not really do much with ZooKeeper when your cluster is in a steady state. If you do need to optimize ZooKeeper, here are a few helpful notes: + + 1. ZooKeeper works best when it has a dedicated machine. ZooKeeper is a timely service and a dedicated machine helps ensure timely responses. A dedicated machine is not required however. + 2. ZooKeeper works best when you put its transaction log and snap-shots on different disk drives. + 3. If you do colocate ZooKeeper with Solr, using separate disk drives for Solr and ZooKeeper will help with performance. When Solr runs an embedded zookeeper server, it defaults to using the solr port plus 1000 for the zookeeper client port. In addition, it defaults to adding one to the client port for the zookeeper server port, and two for the zookeeper leader election port. So in the first example with Solr running at 8983, the embedded zookeeper server used port 9983 for the client port and 9984,9985 for the server ports. @@ -301, +305 @@ === Other === || shardId || Defaults to being automatically assigned based on numShards || value || + === FAQ === + + * Q: I'm seeing lot's of session timeout exceptions - what to do? + A: Try raising the ZooKeeper session timeout by editing solr.xml - see the zkClientTimeout attribute. The minimum session timeout is 2 times your ZooKeeper defined tickTime. The maximum is 20 times the tickTime. The default tickTime is 2 seconds. +
