To calculate vSAN memory consumption in these releases, use this equation:
BaseConsumption + (NumDiskGroups * (DiskGroupBaseConsumption + (SSDMemOverheadPerGB * SSDSize))) +(NumCapacityDisks * CapacityDiskBaseConsumption)
Where: BaseConsumption: is the fixed amount of memory consumed by vSAN per ESXi host. NumDiskGroups: is the number of disk groups in the host, this value should range from 1 to 5. DiskGroupBaseConsumption: is the fixed amount of memory allocated to each individual disk group in the host. This is mainly used to allocate resources used to support inflight operations on a per disk group level. SSDMemOverheadPerGB: is the amount of memory allocated per GB of SSD. SSDSize: is the size of the SSD disk in GB. NumCapacityDisks: is the number of capacity disks in the host (across all the diskgroups). CapacityDiskBaseConsumption: is the amount of memory allocated per capacity disk.
Constants: BaseConsumption = 5426 MB DiskGroupBaseConsumption = 636 MB SSDMemOverheadPerGB (hydrid) = 8 MB SSDMemOverheadPerGB (allflash) = 14 MB CapacityDiskBaseConsumption= 70 MB
Note: In these releases, encryption and deduplication features have no impact on memory consumption.
Example: One disk group per host, all flash configuration: BaseConsumption + (NumDiskGroups * (DiskGroupBaseConsumption + (SSDMemOverheadPerGB * SSDSize))) + (NumCapacityDisks * CapacityDiskBaseConsumption) = 5426 MB + (1 * (636 MB + (14MB * 600))) + (3 * 70 MB) = 14672 MB