What is VMware VSAN 6.2 Erasure Coding?

I have been asked what is the 'Erasure Coding' support in VSAN all about as it gets referenced in the same sentences as the new support for RAID5 and RAID6 configurations (only available in all flash configurations).

VMware is stating Erasure Coding as a term to reference for any data partitioning scheme that allows data to be fragmented but recoverable in case of failure even if some parts  are missing (use of parity). In general reference they are referring to the support of Erasure Coding to represent the fact that they have moved from a mirroring scheme to support both RAID 5 (support for 3+1) and RAID 6 (Support for 4+2) to increase the level of usable data from RAW Capacity across nodes.  

Prior releases only supported a 1+1+witness or worst (1+n where n=failure tolerance but each n was a mirror copy) scheme hence you always needed a minimum 3 nodes to start with but only really got 50% usable capacity at best. This is why the Erasure Code support is getting such big focus as it makes VSAN more efficient with physical resources.

Worth noting that Erasure Coding is not referring to a disk configuration as with RAID but how the fragments are distributed between hosts. It is for this reason that depending on the choice mode also drives the minimum number of hosts required (3 for standard setup, 4 for R5 and 6 for R6).

Welcome VxRail, VCE's Entry into the HCIA Market

You want the ease of a Hyperconverged appliance but still have all those advanced capabilities that service enterprise data centres, then the new VCE VxRail is for! This is not so much an evolution of the VMware EVO:Rail appliances but more a revolution.

Why do I say that? The Achilles heal of EVO:Rail was the lack of flexibility, all you could do was chose between two RAM configurations (no variant in disk or CPU), 128GB or 196GB which for some reason had the 196GB model referred to as the desktop service model... never quite got my head around that one, why wouldn't other services want a larger memory footprint? The other side was the fact that you could only grow your appliance service out by adding additional appliances, start with a 4 node 2U appliance and then grow in increments of 4 from there till you hit the 64 node ceiling (aligned to the maximum size for a HA / VSAN cluster).

Now think the VCE VxRail appliance here we have flexibility that can meet a huge range of use cases, your choices now include:

• Starting point is now 3 nodes (today) and growth can then be in single node increments up to the 64 node maximum
• CPU model options provide a range of 6 cores (single socket) through to 28 cores (dual socket) per node
• Memory configurations from 64GB through to 512GB
• Disk configurations of Hybrid (Flash + Spinning HDD) or all flash ranging from 3.6TB through to 19TB per node 
• Even networking options will support 1G connections on the low end nodes with the standard being dual 10G 

You can also now mix different model configurations and EVO:Rail appliances under the same management. Phew... all that flexibility but with the ease of use that comes with the VxRail appliance.

Some other cool features of note are things such as:

• All the coolness of VSAN 6.2 with Dedupe, compression, flash optimisation, erasure coding, snapshots, cross site HA (yes you can link two remote appliances into a vSphere Metro Cluster)
• VM Level replication with EMC RecoverPoint/VM (yep included) 
• Cloud based storage tiering EMC Cloud Array (yep also included)
• VCE Vision software for service health and interoperabilty compliance monitoring and reporting
• vRealize LogInsight for lag aggregation and analytics
• vSphere Data Protection (EMC Avamar)
• Appliance Market Place, your VxRail App Store for easy request / enablement of additional services

And that is not the end of it, too much to list :)

If you want to have a look for yourself have a look at this demo of the VxRail Manager I recorded!

More information is available at http://www.vce.com/products/hyper-converged/vxrail