This article provides instructions for installing ESXi on a USB drive or SD flash card. However, certain considerations must be made before proceeding with an installation. Ensure that the USB flash drive or SD flash card you are using is supported for installation of ESXi 5.5, ESXi 6.x, ESXi 7.x and/or ESXi 8.x. Consult your server vendor for the appropriate choice of a USB or SD flash storage device.
Note: In the event that your original SD flash card or USB drive fails, these steps can be used in a disaster recovery capacity to get a fully functional ESXi host running as quickly as possible on a replacement USB drive or SD flash card.
VMware vSphere ESXi 5.5
VMware vSphere ESXi 6.0
VMware vSphere ESXi 6.5
VMware vSphere ESXi 6.7
VMware vSphere ESXi 7.0
VMware vSphere ESXi 8.0
Installing ESXi on to a USB flash drive or SD flash card
Note: Installing ESXi on a USB flash drive or SD flash card has the same minimum requirements as installing to typical SCSI or SATA hard disk. For more information, see the Hardware Requirements in the ESXi installation instructions. [ESXi 7.0.x | ESXi 8.0.x]
Note: Some server hardware supports directly mounting ISO to Virtual CD/DVD-ROM (Eg. HP ILO), burning ISO to CD/DVD and inserting CD (Step 2) is not required in those situations.
Limitation when installing on USB flash drive or SD flash card:
Due to the I/O sensitivity of USB and SD devices the installer does not create a scratch partition on these devices. When installing on USB or SD devices, the installer attempts to allocate a scratch region on an available local disk or datastore. If no local disk or datastore is found, /scratch is placed on the ramdisk. After the installation, you should reconfigure /scratch to use a persistent datastore. For more information, see Creating a persistent scratch location for ESXi 8.x/7.x/6.x. VMware recommends using a retail purchased USB flash drive of 16 GB or larger so that the "extra" flash cells can prolong the life of the boot media but high quality parts of 4 GB or larger are sufficient to hold the extended coredump partition.
To workaround this limitation:
For more information, see Install or Upgrade ESXi from a USB Stick by Using a Script.
VMware does not have a specific list of supported SD cards because VMware relies on the support of SD cards by the host hardware vendors. Therefore, VMware supports SD cards only under these conditions:
Note: If you intend to install ESXi on a SD flash storage device while ensuring VMware support for it and you have not purchased a server with Embedded ESXi, consult your server vendor for the appropriate choice of a SD flash storage device.
Impact/Risks:
Disaster Recovery Scenario
If you have a local datastore containing production information and have completed the installation on a replacement USB flash drive or SD flash card in a disaster recovery scenario, you may be required perform these additional steps: