Erasure Codes in VMware vSAN versus Storage Arrays

The Purpose of Erasure Coding Data Storage in vSAN versus a Storage Array Comparing Erasure Codes in vSAN versus Traditional Storage Storage Array vSAN Decoupling Cluster Size and Availability Summary Discover more from VMware Cloud Foundation (VCF) Blog Related Articles Erasure Codes in VMware vSAN versus Storage Arrays Integrating VMware Data Services Manager with Harbor for a Production-Ready Registry NVMe Memory Tiering Design and Sizing on VMware Cloud Foundation 9 Part 3: Sizing for Success Data availability is a core competency of enterprise storage systems. For decades, these systems have attempted to deliver high levels of data availability while ensuring that performance and space efficiency expectations are also met. Achieving all three at the same time is not easy. Erasure coding has played an important role in storing data in a resilient yet space-efficient way. This post will help you better understand how erasure coding is implemented in VMware vSAN, how it is different from what may be found in traditional storage arrays, and how best to interpret an erasure code’s capabilities with data availability. The primary responsibility of any storage system is to give back the bit of data that has been requested. To ensure it can do this reliably, storage systems must store that data in a resilient way. A simple form of data resilience would be through the use of multiple copies, or “mirrors” that would help maintain availability in the event of some type of discrete failure in the storage system, such as a disk in a storage array, or a host in a distributed storage system like vSAN. One of the challenges with this approach is storing full copies of data becomes very costly in terms of capacity consumption. An additional copy would double the amount of data stored, while two additional copies would triple the amount of data stored. Erasure codes are used to store data in a resilient way, but with much more space efficiency relative to traditional mirroring of data. It does not use the approach of copies.