Solandra，从别名上就能看出来，其实它就是结合了 Solr 与 Cassandra 的实时搜索引擎程序。

其特性如下：

• 支持Solr的大多数默认特性 (search, faceting, highlights)
• 数据复制，分片，缓存及压缩这些都由Cassandra来进行
• Multi-master (任意结点都可供读写)
• 实时性高，写操作完成即可读到
• Easily add new SolrCores w/o restart across the cluster 轻松添加及重启结点

这是来自官方的介绍：

Solandra is a real-time distributed search engine built on Apache Solr and Apache Cassandra.

At its core, Solandra is a tight integration of Solr and Cassandra, meaning within a single JVM both Solr and Cassandra are running, and documents are stored and disributed using Cassandra's data model.

Solandra makes managing and dynamically growing Solr simple(r).

For more information please see the wiki

Requirements:

Java >= 1.6

Features:

• Supports most out-of-the-box Solr functionality (search, faceting, highlights)
• Replication, sharding, caching, and compaction managed by Cassandra
• Multi-master (read/write to any node)
• Writes become available as soon as write succeeds
• Easily add new SolrCores w/o restart across the cluster

Getting started:

The following will guide you through setting up a single node instance of Solandra.

From the Solandra base directory:

mkdir /tmp/cassandra-data ant cd solandra-app; bin/solandra 

Now that Solandra is running you can run the demo:

cd http://www.cnblogs.com/reuters-demo ./1-download_data.sh ./2-import_data.sh While data is loading, open the file ./website/index.html in your favorite browser. 

Embedding in an existing cassandra distribution

To use an existing Cassandra distribution perform the following steps.

1. Download your Cassandra distribution
2. Unzip it the directory of your choice

3. Run the following solandra ant task to deploy the necessary files into the unzipped dir

   ant -Dcassandra={unzipped dir} cassandra-dist

4. You can now start Solr within Cassandra by using $CASSANDRA_HOME/bin/solandra command. Cassandra now takes two optional properties: -Dsolandra.context and -Dsolandra.port for the context path and the Jetty port.

Limitations

Solandra uses Solr's built in distributed searching meachanism. Most of its limitations are covered here:

http://wiki.apache.org/solr/DistributedSearch#Distributed_Searching_Limitations