Distributed data store

A distributed data store is a where information is stored on more than one , often in a fashion. It is usually specifically used to refer to either a where users store information on a number of nodes, or a in which users store information on a number of peer network nodes.

Contents

Distributed databases

are usually that make a quick access to data over a large number of nodes possible. Some distributed databases expose rich query abilities while others are limited to a semantics. Examples of limited distributed databases are ‘s , which is much more than a or a , ‘s and .

As the ability of arbitrary querying is not as important as the , designers of distributed data stores have increased the latter at an expense of consistency. But the high-speed read/write access results in reduced consistency, as it is not possible to have both , availability, and partition tolerance of the network, as it has been proven by the .

Peer network node data stores

In peer network data stores, the user can usually reciprocate and allow other users to use their computer as a storage node as well. Information may or may not be accessible to other users depending on the design of the network.

Most peer-to-peer networks do not have distributed data stores in that the user’s data is only available when their node is on the network. However, this distinction is somewhat blurred in a system such as , where it is possible for the originating node to go offline but the content to continue to be served. Still, this is only the case for individual files requested by the redistributors, as contrasted with a network such as Freenet where all computers are made available to serve all files.

Distributed data stores typically use an error detection and correction technique. Some distributed data stores (such as over NNTP) use forward error correction techniques to recover the original file when parts of that file are damaged or unavailable. Others try again to download that file from a different mirror.

Examples

Distributed non-relational databases

  • , former data store of Facebook
  • , the data store of
  • , used by , and others
  • of
  • , current data store of Facebook’s Messaging Platform
  • , data store used by , , and others.
  • , from
  • , data store used by

Peer network node data stores

See Also on BitcoinWiki

Source

http://wikipedia.org/