5.6.1.1 Host Memory Requirements
vSAN memory requirements are defined based on the number of disk groups and disks that the ESXi hypervisor manages. To support the maximum number of disk groups, 32 GB of RAM is required.
Note A best practice is to assign a consistent amount of RAM to each host in the cluster.
If there are separate host configurations with disparate amounts of RAM in the hosts, it is recommended to create multiple vSAN clusters. Other considerations when calculating memory requirements for hosts participating in a vSAN cluster include:
• vSAN scales back on its memory usage when hosts have less than 32 GB of memory.
• vSAN consumes additional memory when the number of nodes in the cluster is greater than 32.
• All flash vSAN configurations consume additional memory resources when compared to hybrid configurations.
For more information about sizing and designing a vSAN cluster, see the following documents:
• VMware Virtual SAN 6.0 Design and Sizing Guide
• VMware Virtual SAN Diagnostics and Troubleshooting Reference Manual