Advantages | Drawbacks |
Simplicity – The simplest option available whether a RAID1 mirror or USB/SD solution is used. Lower cost compute nodes – Boot from removable media allows organizations to purchase less expensive diskless servers. Servers are potentially lower cost because no local disks or RAID card is required. Lower power consumption per compute node – Due to decreased power requirement for local disks. Less heat generated by server – As a result of less moving parts and lower power consumption. No moving parts on host – Having no moving parts on the server results in lower mean times to failure for the hardware, reducing operational costs. vSAN – In a typical vSAN environment, hosts are configured to boot from USB, SD, or other non-persistent storage to maximize the number of persistent disk slots available on the hardware, thereby increasing the potential for virtual machine storage. | Scratch partitions – ESXi never creates scratch partitions on USB flash drives or SD cards, even if they have the capacity, because the potentially heavy disk I/O from the userworld swap could damage them. Media quality – The design must specify industrial grade SD cards or USB devices for the ESXi hypervisor installation (redundantly configured in RAID1 if supported by the hardware). For more VMware recommendations when booting hosts from non-persistent storage, see the VMware vSphere Installation and Setup document at https://pubs.vmware.com/vsphere-60/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-60-installation-setup-guide.pdf. |