What is Erasure Coding and When Should it Be Used?

RAID vs. Erasure Coding: Advanced Data Protection Strategies

RAID (Redundant Array of Independent Disks) has long been a reliable method for protecting data. It safeguards against data loss due to bad blocks or disk failures by either mirroring data across multiple disks or using parity blocks, which allow for recovery of failed blocks. However, a newer approach called erasure coding is gaining traction as an alternative.

How Erasure Coding Works

Erasure coding works by breaking data into multiple fragments and placing them in different locations. These locations can be disks within an array or, more commonly, distributed nodes. For example, if the data is spread over 16 nodes, only 10 are needed to recover the full dataset. This means that the data remains protected even if up to six nodes fail. The benefit of erasure coding is that when a node fails, the other nodes participate in the replacement process, making it less CPU-intensive than rebuilding with RAID in a single array.

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Applications of Erasure Coding

Erasure coding is particularly useful in environments that require scaled-out storage, such as cloud storage, where it is commonly used for object storage. It has proven to be effective in protecting petabytes of cold, backup, or archival data spread across multiple locations in the cloud. Although RAID remains an option, it requires double the storage capacity, which can be inefficient for certain use cases, but it eliminates the need for rebuilds.

When to Use RAID or Erasure Coding

RAID is still a strong choice for safeguarding active, primary data. It keeps data safe within the data center, and rebuilds are performed without taxing available WAN bandwidth. On the other hand, erasure coding is better suited for large-scale, distributed environments where data is spread across various locations.

To choose between RAID and erasure coding, you need to assess the impact each strategy would have on your data protection needs, considering factors like storage efficiency, performance, and recovery requirements.

Both RAID and erasure coding have their advantages, and often, the best choice will depend on the specific demands of your organization’s data management and protection strategy.

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