7.0

Storage Behavior
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.
Caution ESXi overwrites any disks that appear to be blank. Disks are considered to be blank
if they do not have a valid partition table or partitions. If you are using software that uses such
disks, in particular if you are using logical volume manager (LVM) instead of, or in addition to,
conventional partitioning schemes, ESXi might cause local LVM to be reformatted. Back up your
system data before you power on ESXi for the first time.
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.
You might want to override this default behavior if, for example, you use shared storage devices
instead of local storage. To prevent automatic disk formatting, detach the local storage devices
from the host under the following circumstances:
n Before you start the host for the first time.
n 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.
VMware ESXi Installation and Setup
VMware, Inc. 226