quick faq - erasure coding

Quick FAQ

Quick FAQ

Quick FAQWhat is Erasure Coding and how does it work?

What is Erasure Coding and how does it work?


EncodingDecodingSimple example for a 3/1 erasure encoding


Simple example for a 3/1 erasure encoding

We solve for x:

OR

x+y=12 [+] x-y= 22x =14 [2] X = 72x+ y=19 [+] x- y= 23x =21 [3] X = 7EncodingDecoding



We solve for x:

x+y=12 [+] x-y= 22x =14 [2] X = 7EncodingDecoding



We solve for x:

OR

Then we solve for y:

x+y=12 [+] x-y= 22x =14 [2] X = 72x+ y=19 [+] x- y= 23x =21 [3] X = 77+y=12 [-7] y=5 EncodingDecoding



We solve for x:

OR


OR x+y=12 [+] x-y= 22x =14 [2] X = 72x+ y=19 [+] x- y= 23x =21 [3] X = 77-y= 2 [-7] -y=-5 [*-1] y=5 7+y=12 [-7] y=5 EncodingDecoding


What is Erasure Coding and how does it work?Erasure Coding is a data protection scheme that breaks data into shards (fragments) that are encoded with parity (redundant data), and then stored across multiple storage media and locations.


Why you should care


Why you should careYou only need a subset of the shards to rehydrate data.


Why you should careYou only need a subset of the shards to rehydrate data.You can replace failed components when convenient, without taking the system offline.


Why you should careYou only need a subset of the shards to rehydrate data.You can replace failed components when convenient, without taking the system offline.You can reduce CAPEX and OPEX compared with mirroring/replication approaches.

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What is Erasure Coding and how does it work?Erasure Coding encodes data and compartmentalizes it such that only a subset of the pieces are required to recreate the original information.

What is Erasure Coding and how does it work?Erasure Coding encodes data and compartmentalizes it such that only a subset of the pieces are required to recreate the original information.

For example: 5/2 encoding requires (5-2) of 5 pieces to rehydrate it10/3 encoding requires (10-3) of 10 pieces 18/5 requires (18-5) of 18etc.


Simple example for a 18/5 erasure encoding We solve for x:

OR


OR

x+y=12 [+] x-y= 22x =14 [2] X = 72x+ y=19 [+] x- y= 23x =21 [3] X = 77-y= 2 [-7] -y=-5 [*-1] y=5 7+y=12 [-7] y=5 EncodingDecoding

1 18 2

Any 13 of 18 equations to decode object

Thanks for watchingClay RyderDCS Marketing itblog.sandisk.com/author/clayryder

quick faq - erasure coding

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