ChordEr

This is an implementation for the DHT "Chord", as presented in the paper https://pdos.csail.mit.edu/papers/chord:sigcomm01/chord_sigcomm.pdf written in Erlang, for the Distributed Systems Course, 9th Semester, National Technical University of Athens.

Authors: Vasilis Kontonis, Michalis Kokologiannakis.

Course info and details (in greek): http://www.cslab.ntua.gr/courses/distrib/

• Licence
• Dependencies
• Installing
• Usage
• Features

Licence

This program is distributed under the GPL, version 3 or later. Please see the COPYING file for details.

Dependencies

In order to use the tool, you only need a working version of Erlang.

Installing

• Download ChordEr's sources or clone this repository.

• For a default build (w/ eventual consistency):

    make
  

• For linearizability (w/ chain replication):

    make chain
  

• To build test functions:

       	make test
  

Usage

• To create a ring, open an Erlang shell and enter the command:

    dht:join(Int).
  

  where Int is any integer.

• To add nodes in an existing ring enter the command:

    dht:join(Int, Node).
  

  where Int is any integer, and Node a process already in the ring.

• To remove a node from an existing ring use:

    dht:stop(Node).
  

• To insert data enter the command:

    dht:store(Key, Value, Node).
  

• To delete data enter the command:

    dht:remove(Key, Node)
  

• To search for a key and its corresponding data use:

    dht:locate(Key, Node).
  

• To get the data from all nodes use:

    dht:locate("*", Node).
  

Features

Some features of ChordEr are:

• Support for concurrent node joins
• Efficient implementation of finger tables
• Logarithmic data lookup time (O(log n))
• Logarithmic time for node joins (O(log n))
• Data replication (default: eventual consistency -- linearizability w/ chain replication also offered)