When you start ESXi, the host enters an autoconfiguration phase during which system storage devices are configured with defaults.
When you reboot the ESXi host after installing the ESXi image, the host configures the system storage devices with default settings. By default, all visible blank internal disks are formatted with VMFS, so you can store virtual machines on the disks. In ESXi Embedded, all visible blank internal disks with VMFS are also formatted by default.
On the hard drive or USB device that the ESXi host is booting from, the disk-formatting software retains existing diagnostic partitions that the hardware vendor creates. In the remaining space, the software creates the partitions described below.
Partitions Created by ESXi on the Host Drive
For fresh installations, several new partitions are created for the boot banks, scratch partition, locker, and core dump. Fresh ESXi installations use GUID Partition Tables (GPT) instead of MSDOS-based partitioning. The installer creates boot banks of variying size depending on the size of the disk. For more information on the scratch partition see About the Scratch Partition.
The installer affects only the installation disk. The installer does not affect other disks of the server. When you install on a disk, the installer overwrites the entire disk. When the installer autoconfigures storage, the installer does not overwrite hardware vendor partitions.
To create the VMFS datastore, the ESXi installer requires a minimum of 128 GB of free space on the installation disk.
- Before you start the host for the first time.
- Before you start the host after you reset the host to the configuration defaults.
To override the VMFS formatting if automatic disk formatting already occurred, you can remove the datastore. See the vCenter Server and Host Management documentation.