Erasure coding protects data by segmenting it into shards that are parity encoded and distributed across various storage locations, ensuring resilience against multiple failures. It allows for data access without rebuild time even during hardware failures and provides protection at a lower cost than traditional mirroring. This method emphasizes data protection over hardware concerns, needing only a subset of shards to restore the original data.

1. Quick FAQ
How Does Erasure Coding
Protect Data?

2. How Does Erasure Coding Protect Data?
RAID protects disk drives
Erasure Code protects data
Erasure Code
Data
“Raid6.svg” by CBurnett, DrJolo Licensed under Creative Commons By Attribution-ShareAlike 3.0 (http://creativecommons.org/licenses/by-sa/3.0/), via Wikimedia Commons

3. Protecting Your Data with Erasure Coding
• Erasure code is applied
Erasure Code
Data• First object is received
• Data is committed to disk
• Second object is received
• Erasure code applied to new data
• Data is committed to (potentially different) disks
Protection against multiple concurrent failures
Highly resilient
No concept of rebuild time
Data rehydrates on the fly
Only a subset of the shards is required

4. How Does Erasure Coding Protect Data?
Erasure Coding protects data by breaking it into shards that are parity encoded and then
stored across multiple storage media and locations.
Why you should care
• You can focus on protecting data, not hardware.
• You only need a subset of the shards to rehydrate data.
• You can always access your data. Even with hardware failure, there is no data rebuild time.
• You can protect data at a fraction of the expense and overhead of mirroring/replication*.
*per Western Digital Corporation internal testing: using 3-geo erasure coding requires 1.57x to 1.88x storage capacity compared with 3x required for triple mirroring

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

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