In cases of data loss, erasure coding is an alternative form of data protection in which data is broken into fragments and stored across a set of different locations or storage media, like object storage

1. Quick FAQ

2. Quick FAQ
What is Erasure Coding and
how does it work?

3. What is Erasure Coding and how does it work?

4. What is Erasure Coding and how does it work?
Encoding
Decoding
Simple example for a 3/1 erasure encoding

5. What is Erasure Coding and how does it work?
Simple example for a 3/1 erasure encoding
• We solve for x:
OR
x+y=12 [+]
x-y= 2
2x =14 [∕2]
X = 7
2x+ y=19 [+]
x- y= 2
3x =21 [∕3]
X = 7
Encoding
Decoding

6. What is Erasure Coding and how does it work?
Simple example for a 3/1 erasure encoding
• We solve for x:
x+y=12 [+]
x-y= 2
2x =14 [∕2]
X = 7
Encoding
Decoding

7. What is Erasure Coding and how does it work?
Simple example for a 3/1 erasure encoding
• We solve for x:
OR
• Then we solve for y:
x+y=12 [+]
x-y= 2
2x =14 [∕2]
X = 7
2x+ y=19 [+]
x- y= 2
3x =21 [∕3]
X = 7
7+y=12 [-7]
y=5
Encoding
Decoding

8. What is Erasure Coding and how does it work?
Simple example for a 3/1 erasure encoding
• We solve for x:
OR
• Then we solve for y:
OR
x+y=12 [+]
x-y= 2
2x =14 [∕2]
X = 7
2x+ y=19 [+]
x- y= 2
3x =21 [∕3]
X = 7
7-y= 2 [-7]
-y=-5 [*-1]
y=5
7+y=12 [-7]
y=5
Encoding
Decoding

9. What is Erasure Coding and how does it work?

10. 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.

11. 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

12. 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
• You only need a subset of the shards to rehydrate data.

13. 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
• You only need a subset of the shards to rehydrate data.
• You can replace failed components when convenient, without taking the system offline.

14. 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
• You 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.

15. Thanks for watching
Clay Ryder
DCS Marketing
itblog.sandisk.com/author/clayryder

16. © 2017 Western Digital Corporation. All rights reserved. Western Digital and the Western Digital Logo are registered trademarks of Western Digital Corporation
or its affiliates in the U.S. and/or other countries. All other marks are the property of their respective owners.
"Faster Does It" Kevin MacLeod (incompetech.com) — Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0/
@WesternDigiDC
SanDisk Data Center Solutions
@BigDataFlash
HGST, a Western Digital brand

17. 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.

18. 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 it
10/3 encoding requires (10-3) of 10 pieces
18/5 requires (18-5) of 18
etc.

19. What is Erasure Coding and how does it work?
Simple example for a 18/5 erasure encoding
• We solve for x:
OR
• Then we solve for y:
OR
x+y=12 [+]
x-y= 2
2x =14 [∕2]
X = 7
2x+ y=19 [+]
x- y= 2
3x =21 [∕3]
X = 7
7-y= 2 [-7]
-y=-5 [*-1]
y=5
7+y=12 [-7]
y=5
Encoding
Decoding
… …1 182
Any 13 of 18
equations to
decode object

20. Thanks for watching
Clay Ryder
DCS Marketing
itblog.sandisk.com/author/clayryder