How to Remove Storage Devices from ESXi Hosts

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Unmounting a LUN checklist

Before unmounting a LUN, ensure that:

  • If the LUN is being used as a VMFS datastore, all objects (such as virtual machines, snapshots, and templates) stored on the VMFS datastore are unregistered or moved to another datastore.Note: All CD/DVD images located on the VMFS datastore must also be unregistered from the virtual machines.
  • The datastore is not used for vSphere HA heartbeat.
  • The datastore is not part of a datastore cluster.
  • The datastore is not managed by Storage DRS.
  • The datastore is not configured as a diagnostic coredump partition.
  • Storage I/O Control is disabled for the datastore.
  • No third-party scripts or utilities running on the ESXi host can access the LUN that has issue. If the LUN is being used as a datastore, unregister all objects (such as virtual machines and templates) stored on the datastore.
  • If the LUN is being used as an RDM, remove the RDM from the virtual machine. Click Edit Settings, highlight the RDM hard disk, and click Remove. Select Delete from disk if it is not selected, and click OK.Note: This destroys the mapping file, but not the LUN content.
  • Check if the LUN/datastore is used as the persistent scratch location for the host.This PowerCLI script can be used to check the current scratch location:

$vcServer = “vCenter01”
$cluster = “CL01”
$esxCred = Get-Credential
Connect-VIServer $vcServer | Out-Null
#Connect to ESX hosts in cluster
foreach ($esx in Get-Cluster $cluster | Get-VMHost) {
Connect-VIServer $esx -Credential $esxCred | Out-Null
Get-VMHostAdvancedConfiguration -Name “ScratchConfig.ConfiguredScratchLocation”

Note: When using the vSphere Web Client with vSphere 5.1, 5.5 and 6.0, only these checks are performed during the datastore unmount operation:

  • Host should not have any virtual machines residing on this datastore
  • Host should not use the datastore for HA heartbeats

Obtaining the NAA ID of the LUN to be removed

From the vSphere Client, this information is visible in the Properties window of the datastore.

From the ESXi host, run this command:

# esxcli storage vmfs extent list

You see output similar to:

Volume Name VMFS UUID Extent Number Device Name Partition
———– ———————————– ————- ———————————— ———
datastore1 4de4cb24-4cff750f-85f5-0019b9f1ecf6 0 naa.6001c230d8abfe000ff76c198ddbc13e 3
Storage2 4c5fbff6-f4069088-af4f-0019b9f1ecf4 0 naa.6001c230d8abfe000ff76c2e7384fc9a 1
Storage4 4c5fc023-ea0d4203-8517-0019b9f1ecf4 0 naa.6001c230d8abfe000ff76c51486715db 1
LUN01 4e414917-a8d75514-6bae-0019b9f1ecf4 0 naa.60a98000572d54724a34655733506751 1

Make a note of the NAA ID of the datastore to use this information later in this procedure.

Note: Alternatively, you can run the esxcli storage filesystem list command, which lists all file systems recognized by the ESXi host.

Unmounting a LUN using the vSphere Client

To unmount a LUN from an ESXi 5.0 host using the vSphere Client:

  1. If the LUN is an RDM, skip to step 2. Otherwise, in the Configuration tab of the ESXi host, click Storage. Right-click the datastore being removed, and click Unmount.A Confirm Datastore Unmount window appears. When the prerequisite criteria have been passed, click OK.Note: To unmount a datastore from multiple hosts in the vSphere Client, click Hosts and Clusters > Datastores and Datastore Clusters view (Ctrl+Shift+D). Perform the unmount task and select the appropriate hosts that should no longer access the datastore to be unmounted.
  2. Click the Devices view (under Configuration > Storage):                          
  3. Right-click the NAA ID of the LUN (as noted above) and click Detach. A Confirm Device Unmount window is displayed. When the prerequisite criteria are passed, click OK. Under the Operational State of the Device, the LUN is listed as Unmounted.Note: The Detach function must be performed on a per-host basis and does not propagate to other hosts in vCenter Server. If a LUN is presented to an initiator group or storage group on the SAN, the Detach function must be performed on every host in that initiator group before unmapping the LUN from the group on the SAN. Failing to follow this step results in an all-paths-down (APD) state for those hosts in the storage group on which Detach was not performed for the LUN being unmapped.
  4. Confirm if the LUN is successfully detached. The LUN can then be safely unpresented from the SAN. For more information, contact your storage array vendor.
  5. Perform a rescan on all ESXi hosts which had visibility to the LUN. The device is automatically removed from the Storage Adapters.

When the device is detached, it stays in an unmounted state even if the device is re-presented (that is, the detached state is persistent). To bring the device back online, the device must be attached.

If you want the device to permanently decommission from an ESXi host, manually remove the NAA entries from the host configuration:

  1. To list the permanently detached devices, run this command:# esxcli storage core device detached listYou see output similar to:Device UID State
    ———————————— —–
    naa.50060160c46036df50060160c46036df off
    naa.6006016094602800c8e3e1c5d3c8e011 off
  2. To permanently remove the device configuration information from the system, run this command:# esxcli storage core device detached remove -d NAA_IDFor example:# esxcli storage core device detached remove -d naa.50060160c46036df50060160c46036df

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