Purpose
When performing troubleshooting with ESX storage, you may use command line tools which require you to identify a specific disk or LUN connected to ESX. This article explores different ways to identify these disks.
Resolution
ESX 3.X
Use these commands to collect disk and LUN information from within ESX.
- The command esxcfg-mpath -l generates a compact list of the LUNs currently connected to the ESX host.The output appears similar to:
iScsi sw iqn.1998-01.com.vmware:esxhost-41e85afe<->iqn.1992-04.com.iscsi:a0vmhba32:0:0by preferred
iScsi sw iqn.1998-01.com.vmware:esxhost-41e85afe<->iqn.1992-04.com.iscsi:b0vmhba32:1:0tive
- The command esxcfg-vmhbadevs -m generates a compact list of the LUNs currently connected to the ESX host.The output appears similar to:
vmhba2:0:4:1 /dev/sdc1 48fbd8e5-c04f6d90-1edb-001cc46b7a18
vmhba2:0:3:1 /dev/sdb1 48fbd8be-b9638a60-aa72-001cc46b7a18
vmhba32:0:1:1 /dev/sde1 48fe2807-7172dad8-f88b-0013725ddc92
vmhba32:0:0:1 /dev/sdd1 48fe2a3d-52c8d458-e60e-001cc46b7a18
- The command ls -alh /vmfs/devices/disks lists the possible targets for certain storage operations.The output appears similar to:
lrwxrwxrwx 1 root root 60 Oct 16 12:54 vmhba2:0:3:1 ->vml.0200030000600805f300124a90ca40a0bcd05c00294d5341313030:1
lrwxrwxrwx 1 root root 58 Oct 16 12:54 vmhba2:0:4:0 ->vml.0200040000600805f300124a9006d5bbdeb08b002a4d5341313030
lrwxrwxrwx 1 root root 60 Oct 16 12:54 vmhba2:0:4:1 ->vml.0200040000600805f300124a9006d5bbdeb08b002a4d5341313030:1
lrwxrwxrwx 1 root root 58 Oct 16 12:54 vmhba2:1:3:0 ->vml.0200030000600805f300124a90ca40a0bcd05c00294d5341313030
lrwxrwxrwx 1 root root 60 Oct 16 12:54 vmhba2:1:3:1 ->vml.0200030000600805f300124a90ca40a0bcd05c00294d5341313030:1
lrwxrwxrwx 1 root root 58 Oct 16 12:54 vmhba2:1:4:0 ->vml.0200040000600805f300124a9006d5bbdeb08b002a4d5341313030
lrwxrwxrwx 1 root root 60 Oct 16 12:54 vmhba2:1:4:1 ->vml.0200040000600805f300124a9006d5bbdeb08b002a4d5341313030:1
The following are definitions for some of the identifiers and their conventions:
- vmhba<Adapter>:<Target>:<LUN>This identifier
can be used to identify either a LUN or a path to the LUN. When ESX
detects that paths associated to one LUN, each path is assigned
this identifier. The entire LUN then inherits the same name as the
first path. When using this identifier for an entire LUN, the
identified is called the canonical name. When this identifier is used
for a path it is called the path name. These naming conventions may
vary from ESX host to ESX host, and may change if storage hardware
replaced. This identifier is generally used for operations with
utilities such as vmkfstools.
Example: vmhba1:0:0 = Adapter 1, Target 0, and LUN 0. - vmhba<Adapter>:<Target>:<LUN>:<Partition>This identifier is used in the context of a canonical name and is used to identify a partition on the LUN or disk. In addition to the canonical name, there is a :<Partition> appended to the end of the identifier. The <Partition> represents the partition number on the LUN or Disk. If the <Partition>is specified as 0, then it identifies the entire disk instead of only one partition. These naming conventions may vary from ESX host to ESX host, and may change if storage hardware replaced. This identifier is generally used for operations with utilities such as vmkfstools.
- vml.<VML> or vml.<VML>:<Partition>The VML Identifier can be used interchangeably with the canonical name. Appending the:<Partition> works in the same way described above. This identifier is generally used for operations with utilities such as vmkfstools.
- /dev/sd<Device Letter> or /dev/sd<Device Letter><Partition>This naming convention is not VMware specific. This convention is used exclusively by the service console and open source utilities which come with the service console. The <Device Letter>represents the LUN or Disk and is assigned by the service console during boot. The optional<Partition> represents the partition on the LUN or disk. These naming conventions may vary from ESX host to ESX host, and may change if storage hardware replaced. This identifier is generally used for operations with utilities such as fdisk and dd.
- <UUID>The <UUID> is a unique number assigned to a VMFS volume upon the creation of the volume. It may be included in syntax where you need to specify the full path of specific files on a datastore.
Use these commands to collect disk and LUN information from within ESX:
- The command esxcfg-mpath -b generates a compact list of LUNs currently connected to the ESX host.The output appears similar to:
vmhba33:C0:T1:L0 LUN:0 state:active iscsi Adapter: iqn.1998-01.com.vmware:bs-tse-i137-35c1bf18 Target: IQN=iqn.2001-05.com.equallogic:0-8a0906-5b4ecdf03-fed456688e24a8da-bs-tse-vc40-250g Alias= Session=00023d000001 PortalTag=1
- The command esxcfg-scsidevs -l generates a list of LUNs currently connected to the ESX host.The output appears similar to:
Device Type: Direct-Access
Size: 139890 MB
Display Name: Local ServeRA Disk (mpx.vmhba0:C0:T0:L0)
Plugin: NMP
Console Device: /dev/sdb
Devfs Path: /vmfs/devices/disks/mpx.vmhba0:C0:T0:L0
Vendor: ServeRA Model: 8k-l Mirror Revis: V1.0
SCSI Level: 2 Is Pseudo: false Status: on
Is RDM Capable: false Is Removable: false
Is Local: true
Other Names:
vml.0000000000766d686261303a303a30
- The command ls -alh /vmfs/devices/disks lists the possible targets for certain storage operations.The output appears similar to:
lrwxrwxrwx 1 root root 21 Oct 16 13:00 vml.0000000000766d686261303a303a30:1-> mpx.vmhba0:C0:T0:L0:1
lrwxrwxrwx 1 root root 21 Oct 16 13:00 vml.0000000000766d686261303a303a30:2-> mpx.vmhba0:C0:T0:L0:2
lrwxrwxrwx 1 root root 21 Oct 16 13:00 vml.0000000000766d686261303a303a30:3-> mpx.vmhba0:C0:T0:L0:3
lrwxrwxrwx 1 root root 21 Oct 16 13:00 vml.0000000000766d686261303a303a30:5-> mpx.vmhba0:C0:T0:L0:5
lrwxrwxrwx 1 root root 36 Oct 16 13:00vml.020000000060060160b4111600624c5b749c7edd11524149442035 ->naa.60060160b4111600624c5b749c7edd11
lrwxrwxrwx 1 root root 38 Oct 16 13:00vml.020000000060060160b4111600624c5b749c7edd11524149442035:1 ->naa.60060160b4111600624c5b749c7edd11:1
The following are definitions for some of identifiers and their conventions:
- naa.<NAA>NAA stands for Network Addressing Authority identifier. The number is guaranteed to be unique to that LUN. The NAA identifier is the preferred method of identifying LUNs and the number is generated by the storage device. Since the NAA is unique to the LUN, if the LUN is presented the same way across all ESX hosts, the NAA identifier remains the same.
- naa.<NAA>:<Partition>The <Partition> represents the partition number on the LUN or Disk. If the <Partition> is specified as 0, it identifies the entire disk instead of only one partition. This identifier is generally used for operations with utilities such as vmkfstools.
- mpx.vmhba<Adapter>:C<Channel>:T<Target>:L<LUNormpx.vmhba<Adapterormpx.vmhba<Adapter>:C<Channel>:T<Target>:L<LUN>:<Partition>Somehe NAA number described above. In these circumstances, an MPX Identifier is generated by ESX to represent the LUN or disk. The identifier takes the form similar to that of the canonical name of previous versions of ESX with the mpx. prefix. This identifier can be used in the exact same way as the NAA Identifier described above.
- vml.<VML> or vml.<VML>:<Partition>The VML Identifier can be used interchangeably with the NAA Identifier and the MPX Identifier. Appending:<Partition> works in the same way described above. This identifier is generally used for operations with utilities such as vmkfstools.
- vmhba<Adapter>:C<Channel>:T<Target>:L<LUN>This identifier is now used exclusively to identify a path to the LUN. When ESX detects that paths associated to one LUN, each path is assigned this Path Identifier. The LUN also inherits the same name as the first path, but it is now used an a Runtime Name, and not used as readily as the above mentioned identifiers as it may be different depending on the host you are using. This identifier is generally used for operations with utilities such as vmkfstools.
- /dev/sd<Device Letter> or /dev/sd<Device Letter><Partition>This naming convention is not VMware specific. This convention is used exclusively by the service console and open source utilities which come with the service console. The <Device Letter>represents the LUN or Disk and is assigned by the service console during boot. The optional<Partition> represents the partition on the LUN or disk. These naming conventions may vary from ESX host to ESX host and may change if storage hardware replaced. This identifier is generally used for operations with utilities such as fdisk and dd.
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