D-VXR-DS-00: VxRail Design

Minimum clearance above a VxRail rack supports proper airflow management and preserves the required space for sprinkler or fire-suppression systems.

A Pre-deployment Checklist is used to validate that required site prerequisites are in place before a VxRail deployment begins.

VxRail Dynamic Nodes provide compute without a VMware vSAN license, which can reduce licensing costs. They use supported external storage arrays as primary storage and can consume an existing VxRail vSAN datastore through VMware vSAN Cross-Cluster Capacity Sharing.

The vSAN witness appliance must have the same underlying vSphere/vSAN version as the VxRail vSAN environment, and the witness must be provisioned as an external prerequisite before configuring the stretched cluster. A witness host must be in the same vCenter Server inventory as the data-site hosts; it may be either a dedicated physical ESXi host or a vSAN witness appliance.

A 1-failure RAID-5 erasure-coded layout has read-modify-write overhead for partial-stripe writes: the existing data and parity are read, and the changed data and recalculated parity are written. Thus, each front-end write generates four backend I/O operations. VMware documents that RAID-5/6 parity updates inherently amplify I/O through reads, parity calculation, and distribution of updated data and parity.