vSphere Storage - ESXi 5.1 - Documentation - VMware

Managing Storage Devices 15
Manage local and networked storage device that your ESXi host has access to.
This chapter includes the following topics:
n “Understanding Storage Device Naming,” on page 133
n “Storage Refresh and Rescan Operations,” on page 135
n “Identifying Device Connectivity Problems,” on page 138
Understanding Storage Device Naming
Each storage device, or LUN, is identified by several names.
Device Identifiers
Depending on the type of storage, the ESXi host uses different algorithms and conventions to generate an
identifier for each storage device.
SCSI INQUIRY
identifiers.
The host uses the SCSI INQUIRY command to query a storage device and uses
the resulting data, in particular the Page 83 information, to generate a unique
identifier. Device identifiers that are based on Page 83 are unique across all
hosts, persistent, and have one of the following formats:
n naa.number
n t10.number
n eui.number
These formats follow the T10 committee standards. See the SCSI-3
documentation on the T10 committee Web site.
Path-based identifier. When the device does not provide the Page 83 information, the host generates
an mpx.path name, where path represents the path to the device, for example,
mpx.vmhba1:C0:T1:L3. This identifier can be used in the same way as the SCSI
INQUIRY identifies.
Legacy Identifier
The mpx. identifier is created for local devices on the assumption that their path
names are unique. However, this identifier is neither unique nor persistent and
could change after every boot.
In addition to the SCSI INQUIRY or mpx. identifiers, for each device, ESXi generates an alternative legacy
name. The identifier has the following format:
VMware, Inc. 133