Verify that the ESXi hosts in your organization meet the Virtual SAN hardware requirements.

Storage Device Requirements

All capacity devices, drivers, and firmware versions in your Virtual SAN configuration must be certified and listed in the Virtual SAN section of the VMware Compatibility Guide.

Table 1. Storage Device Requirements for Virtual SAN Hosts

Storage Component

Requirements

Cache

  • One SAS or SATA solid state disk (SSD) or PCIe flash device.

  • Before calculating the Number of failures to tolerate, verify that the size of the flash caching device in each disk group provides at least 10 percent of the anticipated storage consumed on the capacity devices, not including replicas such as mirrors.

  • vSphere Flash Read Cache must not use any of the flash devices reserved for Virtual SAN cache.

  • The cache flash devices must not be formatted with VMFS or another file system.

Virtual machine data storage

  • For hybrid group configuration, make sure at least one SAS or NL-SAS magnetic disk is available.

  • For all-flash disk group configuration, make sure at least one SAS or SATA solid state disk (SSD) or PCIe flash device.

Storage controllers

One SAS or SATA host bus adapter (HBA), or a RAID controller that is in passthrough mode or RAID 0 mode.

To avoid issues, consider these points when the same storage controller is backing both vSAN and non-vSAN disks:

Do not mix the controller mode for vSAN and non-vSAN disks to avoid handling the disks inconsistently, which can negatively impact vSAN operation.

  • If the vSAN disks are in passthrough or JBOD mode, the non-vSAN disks must also be in passthrough or JBOD mode.

  • If the vSAN disks are in RAID mode, the non-vSAN disks must also be in RAID mode.

When you use non-vSAN disks for VMFS, use the VMFS datastore only for scratch, logging and core dumps.

Do not run virtual machines from a disk or RAID group that shares its controller with vSAN disks or RAID groups.

Do not passthrough non-vSAN disks to virtual machine guests as Raw Device Mappings (RDMs).

For more information, see https://kb.vmware.com/s/article/2129050.

To learn about controller supported features, such as passthrough and RAID, refer to the vSAN HCL: https://www.vmware.com/resources/compatibility/search.php?deviceCategory=vsan

Memory

The memory requirements for Virtual SAN depend on the number of disk groups and devices that are managed by the ESXi hypervisor. Each host must contain a minimum of 32 GB of memory to accommodate for the maximum number of five disk groups and maximum number of seven capacity devices per disk group.

Flash Boot Devices

If the memory of the ESXi host is 512 GB memory or less, boot the host from a USB, SD, or SATADOM device. When you boot a Virtual SAN host from a USB device or SD card, the size of the boot device must be at least 4 GB.

If the memory of the ESXi host is greater than 512 GB, boot the host from a SATADOM or disk device. When you boot a Virtual SAN host from a SATADOM device, you must use single-level cell (SLC) device and the size of the boot device must be at least 16 GB.

When you boot an ESXi 6.0 host from USB device or from SD card, Virtual SAN trace logs are written to RAMDisk. These logs are automatically offloaded to persistent media during shutdown or system crash (PANIC). This is the only support method for handling Virtual SAN traces when booting an ESXi from USB stick or SD card. Note that if a power failure occurs, Virtual SAN trace logs are not preserved.

When you boot an ESXi 6.0 host from a SATADOM device, Virtual SAN trace logs are written directly to the SATADOM device. Therefore it is important that the SATADOM device meets the specifications outlined in this guide.