Backup Entire USB Drive Containing Bootable Partitions in Debian [duplicate]

Typically, one would backup the ESXi host's configuration and, in the event of a failure, reinstall ESXi to a new USB disk and restore the backup.

It's actually bad practice to use USB boot for VMware ESXi hosts when you don't have shared storage or a VMware cluster.

When you're in a VMware cluster situation, your virtual machines live on a shared NAS or SAN and you're more capable of dealing with a host failure. If you are just running one VMware server, then booting off of USB (or SDHC card) is an unnecessary risk.

Long term, the better solution is to install VMware on actual disks if you're using a single host server. Otherwise, you can take periodic backups of the configuration from the host's shell or command line with:

vim-cmd hostsvc/firmware/backup_config

This produces a web link that you'll be able to browse to and download a tarball of the host's configuration.

Also see: What happens when the USB key or SD card I've installed VMware ESXi on fails?