kumofs is a scalable and highly available distributed key-value store.
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Kumofs is a simple and fast distributed key-value store.

You can use a memcached client library to set, get, CAS or delete values from/into kumofs. Backend storage is Tokyo Cabinet and it will give you great performance.

  • Data is partitioned and replicated over multiple servers.
  • Extreme single node performance; comparable with memcached.
  • Both read and write performance got improved as servers added.
  • Servers can be added without stopping the system.
  • Servers can be added without modifying any configuration files.
  • The system does not stop even if one or two servers crashed.
  • The system does not stop to recover crashed servers.
  • Automatic rebalancing support with a consistency control algorithm.
  • Safe CAS operation support.
  • memcached protocol support.

See following URLs for more details:


Single node performance of kumofs

It measured performance of one server node using three client machines. Each client machine gets 12,800 of 1KB values from the server using 32 threads. The source code is available from frsyuki's repository. (kumofs, voldemort).

Scalability of kumofs

It measured performance of the cluster using 50 client machines. Each client machine gets 1,024,000 entries form the cluster using 32 threads.


Design of kumofs

kumo-servers store data and replicate them into other kumo-servers. kumo-managers watch life or death of kumo-servers and proceed automatic rebalancing when the number of kumo-servers is changed. kumo-gatway relay the requests from client applications to kumo-servers. Because kumo-gateway implements memcached protocol, you can use memcached client library to access kumofs.


Following libraries are required to build kumofs:

Configure and install in the usual way:

$ ./bootstrap  # if needed
$ ./configure
$ make
$ sudo make install


This example runs kumofs on 6-node cluster. Run kumo-manager on mgr1 and mgr2, kumo-server on svr1, svr2 and svr3, then run kumo-gateway on cli1.

[on mgr1]$ kumo-manager -v -l mgr1 -p mgr2
[on mgr2]$ kumo-manager -v -l mgr2 -p mgr1
[on svr1]$ kumo-server  -v -l svr1 -m mgr1 -p mgr2 -s /var/kumodb.tch
[on svr2]$ kumo-server  -v -l svr2 -m mgr1 -p mgr2 -s /var/kumodb.tch
[on svr3]$ kumo-server  -v -l svr3 -m mgr1 -p mgr2 -s /var/kumodb.tch
[       ]$ kumoctl mgr1 attach
[on cli1]$ kumo-gateway -v -m mgr1 -p mgr2 -t 11211
[on cli1]$ # use memcached client on 11211/tcp

See documents for details.

Run on single host

This example runs kumofs on single host.

[localhost]$ kumo-manager -v -l localhost
[localhost]$ kumo-server  -v -m localhost -l localhost:19801 -L 19901 -s ./kumodb1.tch
[localhost]$ kumo-server  -v -m localhost -l localhost:19802 -L 19902 -s ./kumodb2.tch
[localhost]$ kumo-server  -v -m localhost -l localhost:19803 -L 19902 -s ./kumodb3.tch
[localhost]$ kumoctl localhost attach
[localhost]$ kumo-gateway -v -m localhost -t 11211
[localhost]$ # have fun with memcached client on 11211/tcp


Copyright (C) 2009-2010 FURUHASHI Sadayuki

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at


   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   See the License for the specific language governing permissions and
   limitations under the License.

See also NOTICE file.