vSphere Storage - ESXi 5.1 - Documentation - VMware

vSphere Storage
Types of Physical Storage
The ESXi storage management process starts with storage space that your storage administrator preallocates
on different storage systems.
ESXi supports the following types of storage:
Local Storage Stores virtual machine files on internal or directly connected external storage
disks.
Networked Storage Stores virtual machine files on external storage disks or arrays attached to your
host through a direct connection or through a high-speed network.
Local Storage
Local storage can be internal hard disks located inside your ESXi host, or it can be external storage systems
located outside and connected to the host directly through protocols such as SAS or SATA.
Local storage does not require a storage network to communicate with your host. You need a cable connected
to the storage unit and, when required, a compatible HBA in your host.
The following illustration depicts a virtual machine using local SCSI storage.
Figure 1-1. Local Storage
VMFS
Host
virtual
machine
SCSI
In this example of a local storage topology, the host uses a single connection to a storage disk. On that disk,
you can create a VMFS datastore, which you use to store virtual machine disk files.
Although this storage configuration is possible, it is not a recommended topology. Using single connections
between storage arrays and hosts creates single points of failure (SPOF) that can cause interruptions when a
connection becomes unreliable or fails.
ESXi supports a variety of internal or external local storage devices, including SCSI, IDE, SATA, USB, and SAS
storage systems. Regardless of the type of storage you use, your host hides a physical storage layer from virtual
machines.
NOTE You cannot use IDE/ATA or USB drives to store virtual machines.
Local storage devices do not support sharing across multiple hosts. A datastore on a local storage device can
be accessed by only one host.
Because the majority of local storage devices do not support multiple connections, you cannot use multiple
paths to access local storage.
14 VMware, Inc.