Cassandra is a highly scalable, eventually consistent, distributed, structured key-value store. This is a special fork dedicated to running cassandra in tactical environments. Tactical environments are special in the following aspects: 1. bad, unreliable communication. mostly radio based with a lot of noise. 2. communication topology constantly changes. 3. a node can find it self out of the network, or on a subset (partition) of the network 4. high network latencies and more. Project description ------------------- Cassandra brings together the distributed systems technologies from Dynamo and the data model from Google's BigTable. Like Dynamo, Cassandra is eventually consistent. Like BigTable, Cassandra provides a ColumnFamily-based data model richer than typical key/value systems. For more information see http://cassandra.apache.org/ Requirements ------------ * Java >= 1.6 (OpenJDK and Sun have been tested) Getting started --------------- This short guide will walk you through getting a basic one node cluster up and running, and demonstrate some simple reads and writes. * tar -zxvf apache-cassandra-$VERSION.tar.gz * cd apache-cassandra-$VERSION * sudo mkdir -p /var/log/cassandra * sudo chown -R `whoami` /var/log/cassandra * sudo mkdir -p /var/lib/cassandra * sudo chown -R `whoami` /var/lib/cassandra Note: The sample configuration files in conf/ determine the file-system locations Cassandra uses for logging and data storage. You are free to change these to suit your own environment and adjust the path names used here accordingly. Now that we're ready, let's start it up! * bin/cassandra -f Unix: Running the startup script with the -f argument will cause Cassandra to remain in the foreground and log to standard out. Windows: bin\cassandra.bat runs in the foreground by default. To install Cassandra as a Windows service, download Procrun from http://commons.apache.org/daemon/procrun.html, set the PRUNSRV environment variable to the full path of prunsrv (e.g., C:\procrun\prunsrv.exe), and run "bin\cassandra.bat install". Similarly, "uninstall" will remove the service. Now let's try to read and write some data using the Cassandra Query Language: * bin/cqlsh The command line client is interactive so if everything worked you should be sitting in front of a prompt... Connected to Test Cluster at localhost:9160. [cqlsh 2.2.0 | Cassandra 1.2.0 | CQL spec 3.0.0 | Thrift protocol 19.35.0] Use HELP for help. cqlsh> As the banner says, you can use 'help;' or '?' to see what CQL has to offer, and 'quit;' or 'exit;' when you've had enough fun. But lets try something slightly more interesting: cqlsh> CREATE SCHEMA schema1 WITH replication = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 }; cqlsh> USE schema1; cqlsh:Schema1> CREATE TABLE users ( user_id varchar PRIMARY KEY, first varchar, last varchar, age int ); cqlsh:Schema1> INSERT INTO users (user_id, first, last, age) VALUES ('jsmith', 'John', 'Smith', 42); cqlsh:Schema1> SELECT * FROM users; user_id | age | first | last ---------+-----+-------+------- jsmith | 42 | john | smith cqlsh:Schema1> If your session looks similar to what's above, congrats, your single node cluster is operational! For more on what commands are supported by CQL, see https://github.com/apache/cassandra/blob/trunk/doc/cql3/CQL.textile. A reasonable way to think of it is as, "SQL minus joins and subqueries." Wondering where to go from here? * Getting started: http://wiki.apache.org/cassandra/GettingStarted * Join us in #cassandra on irc.freenode.net and ask questions * Subscribe to the Users mailing list by sending a mail to user-subscribe@cassandra.apache.org * Planet Cassandra aggregates Cassandra articles and news: http://planetcassandra.org/