2 research outputs found
Multi-Version Coding
We derive a simple lower bound for the multi-version coding problem
formulated in [1]. We also propose simple algorithms that almost match the
lower bound derived. Another lower bound is proven for an extended version of
the multi-version coding problem introduced in [2]
Multi-Version Coding - An Information Theoretic Perspective of Consistent Distributed Storage
In applications of distributed storage systems to distributed computing and
implementation of key- value stores, the following property, usually referred
to as consistency in computer science and engineering, is an important
requirement: as the data stored changes, the latest version of the data must be
accessible to a client that connects to the storage system. An information
theoretic formulation called multi-version coding is introduced in the paper,
in order to study storage costs of consistent distributed storage systems.
Multi-version coding is characterized by {\nu} totally ordered versions of a
message, and a storage system with n servers. At each server, values
corresponding to an arbitrary subset of the {\nu} versions are received and
encoded. For any subset of c servers in the storage system, the value
corresponding to the latest common version, or a later version as per the total
ordering, among the c servers is required to be decodable. An achievable
multi-version code construction via linear coding and a converse result that
shows that the construction is approximately tight, are provided. An
implication of the converse is that there is an inevitable price, in terms of
storage cost, to ensure consistency in distributed storage systems.Comment: 30 Pages. Extended version of conference publications in ISIT 2014
and Allerton 2014. Revision adds a section, Section VII, and corrects minor
typographical errors in the rest of the documen