Editing Peer-to-peer (section)

===Distributed storage and search===
[[File:Yacy-resultados.png|thumb|right|300px|Search results for the query "[[software libre]]" using [[YaCy]], a free [[distributed search engine]] that runs on a peer-to-peer network instead of making requests to centralized index servers]]
There are both advantages and disadvantages in P2P networks related to the topic of data [[backup]], recovery, and availability. In a centralized network, the system administrators are the only forces controlling the availability of files being shared. If the administrators decide to no longer distribute a file, they simply have to remove it from their servers, and it will no longer be available to users. Along with leaving the users powerless in deciding what is distributed throughout the community, this makes the entire system vulnerable to threats and requests from the government and other large forces.

For example, [[YouTube]] has been pressured by the [[RIAA]], [[MPAA]], and entertainment industry to filter out copyrighted content. Although server-client networks are able to monitor and manage content availability, they can have more stability in the availability of the content they choose to host. A client should not have trouble accessing obscure content that is being shared on a stable centralized network. P2P networks, however, are more unreliable in sharing unpopular files because sharing files in a P2P network requires that at least one node in the network has the requested data, and that node must be able to connect to the node requesting the data. This requirement is occasionally hard to meet because users may delete or stop sharing data at any point.<ref>{{cite journal |year=2003 |title=Looking up data in P2P systems |journal=Communications of the ACM |volume=46 |issue=2 |pages=43–48 |doi=10.1145/606272.606299 |url=http://www.nms.lcs.mit.edu/papers/p43-balakrishnan.pdf |access-date=8 October 2013|last1=Balakrishnan |first1=Hari |last2=Kaashoek |first2=M. Frans |last3=Karger |first3=David |last4=Morris |first4=Robert |last5=Stoica |first5=Ion |citeseerx=10.1.1.5.3597 |s2cid=2731647 }}</ref>

In a P2P network, the community of users is entirely responsible for deciding which content is available. Unpopular files eventually disappear and become unavailable as fewer people share them. Popular files, however, are highly and easily distributed. Popular files on a P2P network are more stable and available than files on central networks. In a centralized network, a simple loss of connection between the server and clients can cause a failure, but in P2P networks, the connections between every node must be lost to cause a data-sharing failure. In a centralized system, the administrators are responsible for all data recovery and backups, while in P2P systems, each node requires its backup system. Because of the lack of central authority in P2P networks, forces such as the recording industry, [[RIAA]], [[MPAA]], and the government are unable to delete or stop the sharing of content on P2P systems.<ref>{{cite web |url=http://www.p2pnews.net/2012/06/14/art-thou-a-peer/ |title=Art thou a Peer? |author=<!--Staff writer(s); no by-line.--> |date=14 June 2012 |website=www.p2pnews.net |access-date=10 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131006022409/http://www.p2pnews.net/2012/06/14/art-thou-a-peer/ |archive-date=6 October 2013 }}</ref>