wiki:FAQ

Version 5 (modified by davidsarah, at 2009-10-20T02:54:51Z) (diff)

add link to architecture doc

Q: What is special about Tahoe-LAFS? Why should anyone care about it instead of other distributed storage systems?

A: Tahoe-LAFS is the first Free Software/Open? Source storage technology which offers provider-independent security. Provider-independent security means that the integrity and confidentiality of your files is guaranteed by mathematics computed on the client side, and is independent of the servers, which may be owned and operated by someone else. To learn more, read our one-page explanation.

Q: Oh, so I should be interested in Tahoe-LAFS only if I'm working on some sort of high-security project?

A: No, no! Unlike most systems Tahoe-LAFS doesn't require you to manage an added layer of hassle in order to gain security. Instead the security properties are baked into the system in such a way that you usually don't even notice that they are there. Even if you don't care about protecting your files from someone spying on them or corrupting them, you might still like to use Tahoe-LAFS because it is an extremely robust and efficient "cloud storage" system in which your files are erasure-coded and distributed across separate servers.

Q: "Erasure-coding"? What's that?

A: You know how with RAID-5 you can lose any one drive and still recover? And there is also something called RAID-6 where you can lose any two drives and still recover. Erasure coding is the generalization of this pattern: you get to configure it for how many drives you could lose and still recover. Tahoe-LAFS is typically configured to upload each file to 10 different drives, where you can lose any 7 of them and still recover the entire file. This gives radically better reliability than typical RAID setups, at a cost of only 3.3 times the storage space that a single copy takes.

Q: Where should I look for current documentation about Tahoe's protocols?

http://allmydata.org/source/tahoe/trunk/docs/architecture.txt