One thing most probably won’t realize is that there is a design consideration with VSAN when it comes to installing ESXi. Many of you have probably been installing ESXi on USB or SD and this is also still supported with VSAN. There is one caveat however and this caveat is around the total number of GBs of memory in a host. The design consideration is fairly straight forward and also documented in the VSAN Design and Sizing Guide. Just to make it a bit easier to find it I copied/pasted it here for your convenience:
- Use SD, USB, or hard disk devices as the installation media whenever ESXi hosts are configured with as much as 512GB memory. Minimum size for USB/SD card is 4GB, recommended 8GB.
- Use a separate magnetic disk or solid-state disk as the installation device whenever ESXi hosts are configured with more than 512GB memory.
You may wonder what the reason is, the reason for this is that VSAN will use the core dump partition to store VSAN traces that can be used by VMware Global Support Services and the VMware Engineering team for root cause analysis when needed. So make sure when configuring host to keep this in mind when going above 512GB of memory.
Please note that this is what has been tested by VMware and will be supported, so this is not just any recommendation but could have impact on support!