mogilefs--glossary
? Glossary ?Terms for common itemsdomainclasskeyminimum replica count (mindevcount)filefiddomain?

Adomain is the top level separation of files. File keys are uniquewithin domains. A domain consists of a set of classes that define thefiles within the domain. Examples of domains: fotobilder, livejournal.

class?

Everyfile is part of exactly one class. A class is part of exactly onedomain. A class, in effect, specifies the minimum replica count of afile. Examples of classes: userpicture, userbackup, phonepost. Classesmay have extra replication policies defined.

key?

Akey is a unique textual string that identifies a file. Keys are uniquewithin domains. Examples of keys: userpicture:34:39, phonepost:93:3834,userbackup:15. Fake structures work too: /pics/hello.png, any string.

minimum replica count (mindevcount)?

Thisis a property of a class. This defines how many times the files in thatclass need to be replicated onto different devices in order to ensureredundancy among the data and prevent loss.

file?

Afile is a defined collection of bits uploaded to MogileFS to store.Files are replicated according to their minimum replica count. Eachfile has a key, is a part of one class, and is located in one domain.Files are the things that MogileFS stores for you.

fid?

Afid is an internal numerical representation of a file. Every file isassigned a unique fid. If a file is overwritten, it is given a new fid.