Keyun Cheng

Clay Codes: Moulding MDS Codes to Yield an MSR Code

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FAST, 2018

Summary

This paper introduces Coupling-layer (Clay) Codes that mixed the MDS code and MRS code. It provides a simplified implementation of decode/repair that MRS can’t achieve in real world. It provides the first implementation of an MSR code with low storage overhead, simutaneously optimality of repair bandwidth, sub-packetization level and disk I/O, uniform repair performance and support multiple node repairs .The authors also modify Ceph to support vector code.

Details

The contribution of this work includes:

  1. Use uncoupled code to generate coupled layer that is an MSR code. It uses a pair of coordinates to represent a layer in Clay Code, then it pairs the vertices and the data as a cube like structure. The transformation of uncoupled layer to Clay code is simple matrix transformation (PFT and PRT).

  2. A special decode algorithm for Clay Code allows 2 nodes failure.

  3. Implementation in Ceph.

Strength

Clay Code is the first implementation of MRS code in real world environment by transforming MDS, thus allowing the benefits introduced by MRS code.

Weakness

N/A