The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My badges

  • Twitter Updates

  • My Flickr Stream

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 4,226 other subscribers

ESXi: finding unmounted VMFS volumes

Posted by jpluimers on 2021/08/26

Sometimes, especially when ESXi thinks a volume is bad, but the ESXi S.M.A.R.T. logging does not indicate so, it boots without mounting some of the VMFS volumes as datastores.

It took me a while to find the right command to list those, but I’m glad I found it:

# esxcfg-volume -l
Scanning for VMFS-3/VMFS-5 host activity (512 bytes/HB, 2048 HBs).
VMFS UUID/label: 552f5788-33e30274-8dba-001f29022aed/850EVO1TBR1B
Can mount: Yes
Can resignature: Yes
Extent name: naa.600605b00aa054a0ff0000210221eaf8:1 range: 0 - 953087 (MB)

Scanning for VMFS-6 host activity (4096 bytes/HB, 1024 HBs).
VMFS UUID/label: 5ad4af1b-f3ae285c-e0f4-0cc47aaa9742/IntelNVMe1TB-BTPY750500091P0H
Can mount: Yes
Can resignature: Yes
Extent name: eui.0000000001000000e4d25cd29be94e01:1 range: 0 - 976639 (MB)

Scanning for VMFS-6 host activity (4096 bytes/HB, 1024 HBs).
VMFS UUID/label: 5ad4aeea-6954841c-470e-0cc47aaa9742/IntelNVMe1TB-BTPY7425047S1P0H
Can mount: Yes
Can resignature: Yes
Extent name: eui.0000000001000000e4d25c0e8dc74e01:1 range: 0 - 976639 (MB)

Scanning for VMFS-3/VMFS-5 host activity (512 bytes/HB, 2048 HBs).
VMFS UUID/label: 552d3e82-ccee005a-b719-001f29022aed/850EVO1TBR1A
Can mount: Yes
Can resignature: Yes
Extent name: naa.600605b004b87fb01cc22b3487cbf9a9:1 range: 0 - 953087 (MB)

It is a similar esxcfg-* command with very long output:

# esxcfg-scsidevs -m
t10.ATA_____WDC_WD3200BEKT2D22F3T0________________________WD2DWXE708P5C200:1 /vmfs/devices/disks/t10.ATA_____WDC_WD3200BEKT2D22F3T0________________________WD2DWXE708P5C200:1 502124c5-cc47df0d-3ef7-a0369f0e1091  0  simplesata
t10.ATA_____SAMSUNG_MZHPV512HDGL2D00000______________S1X1NYAGB09589______:1  /vmfs/devices/disks/t10.ATA_____SAMSUNG_MZHPV512HDGL2D00000______________S1X1NYAGB09589______:1  5791a3e1-0b9368de-4965-0cc47aaa9742  0  Samsung512NVME
t10.ATA_____Samsung_SSD_850_PRO_2TB_________________S3D4NX0HA01043L_____:1   /vmfs/devices/disks/t10.ATA_____Samsung_SSD_850_PRO_2TB_________________S3D4NX0HA01043L_____:1   59a018dd-07a9931a-7135-0cc47aaa9742  0  Samsung850-2TB-S3D4NX0HA01043L
t10.ATA_____Samsung_SSD_850_PRO_2TB_________________S2KMNCAGB04321L_____:1   /vmfs/devices/disks/t10.ATA_____Samsung_SSD_850_PRO_2TB_________________S2KMNCAGB04321L_____:1   59a01b5c-c46ae5be-f4eb-0cc47aaa9742  0  Samsung850-2TB-S2KMNCAGB04321L
naa.5000c50087762d1b:1                                                       /vmfs/devices/disks/naa.5000c50087762d1b:1                                                       59a33f7b-66df7c00-11b0-0cc47aaa9742  0  ST6000VX0001-1SH-Z4D3DZZV
naa.600605b00aa054a0ff000021022683ae:1                                       /vmfs/devices/disks/naa.600605b00aa054a0ff000021022683ae:1                                       532cd010-6e8c01d1-45be-001f29022aed  0  Raid6SSD

or a totally different command than the other way around (listing all mounted datastores):

# esxcli storage vmfs extent list
Volume Name                     VMFS UUID                            Extent Number  Device Name                                                                 Partition
------------------------------  -----------------------------------  -------------  --------------------------------------------------------------------------  ---------
simplesata                      502124c5-cc47df0d-3ef7-a0369f0e1091              0  t10.ATA_____WDC_WD3200BEKT2D22F3T0________________________WD2DWXE708P5C200          1
Samsung512NVME                  5791a3e1-0b9368de-4965-0cc47aaa9742              0  t10.ATA_____SAMSUNG_MZHPV512HDGL2D00000______________S1X1NYAGB09589______           1
Samsung850-2TB-S3D4NX0HA01043L  59a018dd-07a9931a-7135-0cc47aaa9742              0  t10.ATA_____Samsung_SSD_850_PRO_2TB_________________S3D4NX0HA01043L_____            1
Samsung850-2TB-S2KMNCAGB04321L  59a01b5c-c46ae5be-f4eb-0cc47aaa9742              0  t10.ATA_____Samsung_SSD_850_PRO_2TB_________________S2KMNCAGB04321L_____            1
ST6000VX0001-1SH-Z4D3DZZV       59a33f7b-66df7c00-11b0-0cc47aaa9742              0  naa.5000c50087762d1b                                                                1
Raid6SSD                        532cd010-6e8c01d1-45be-001f29022aed              0  naa.600605b00aa054a0ff000021022683ae                                                1

Yes, this has to do with my post earlier today: NVMe and SATA health data on ESXi: some links to investigate.

You can mount the volume persistently (with the -M or --persistent-mount option) or transiently (with the -m or --mount option), where you can either refer to the volume by name or by uuid:

-l|--list               List all volumes which have been
                        detected as snapshots/replicas.
-m|--mount              Mount a snapshot/replica volume, if 
                        its original copy is not online.
-u|--umount             Umount a snapshot/replica volume.
-r|--resignature        Resignature a snapshot/replica volume.
-M|--persistent-mount   Mount a snapshot/replica volume
                        persistently, if its original copy is
                        not online.
-U|--upgrade            Upgrade a VMFS3 volume to VMFS5.
-h|--help               Show this message.

So in my case, I mounted two of the volumes by hand (of which later one of the NVMe devices – IntelNVMe1TB-BTPY750500091P0H – died within warranty and the other – IntelNVMe1TB-BTPY7425047S1P0H – was causing read errors within warranty, so sent both for RMA):

  • # esxcfg-volume --persistent-mount IntelNVMe1TB-BTPY750500091P0H
    Persistently mounting volume IntelNVMe1TB-BTPY750500091P0H
  • # esxcfg-volume --persistent-mount IntelNVMe1TB-BTPY7425047S1P0H
    Persistently mounting volume IntelNVMe1TB-BTPY7425047S1P0H

Alternatively, you can use esxcli to do the same: [Wayback] Mount a Datastore with ESXCLI

Mount a Datastore with ESXCLI

The esxcli storage filesystem commands support mounting and unmounting volumes. You can also specify whether to persist the mounted volumes across reboots by using the --no-persist option.

Use the esxcli storage filesystem command to list mounted volumes, mount new volumes, and unmount a volume. Specify one of the connection options listed in Connection Options for vCLI Host Management Commands in place of <conn_options>.


  1. List all volumes that have been detected as snapshots.

    esxcli <conn_options> storage filesystem list
  2. Run esxcli storage filesystem mount with the volume label or volume UUID.

    esxcli <conn_options> storage filesystem volume mount --volume-label=<label>|--volume-uuid=<VMFS-UUID>


    This command fails if the original copy is online.

What to do next

You can later run esxcli storage filesystem volume unmount to unmount the snapshot volume.

esxcli <conn_options> storage filesystem volume unmount --volume-label=<label>|--volume-uuid=<VMFS-UUID>


Knowing the command made me – through [Wayback] “esxcfg-volume -l” – Google Search – found out many ran in the same issue, including myself (:


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: