Using VMware vSphere On-disk Metadata Analyzer to re-create missing partition tables on VMware ESXi
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Using VMware vSphere On-disk Metadata Analyzer to re-create missing partition tables on VMware ESXi

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Article ID: 345233

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

This article explains steps to use the vSphere On-disk Metadata Analyzer (VOMA) to assist in the resolution of missing partition tables on devices which contain VMFS filesystems.

Note: The VOMA functionality detailed here is added to ESXi 5.5 in patch 04.

For more information on VMware ESXi 5.5 patch 04, see Broadcom ESXi 5.5, Patch Release ESXi550-201501001 (2099265).


Environment

  • VMware vSphere ESXi 6.5
  • VMware vSphere ESXi 5.5
  • VMware vSphere ESXi 6.0

Resolution

To analyze an existing storage device and recreate the partition table on an ESXi 5.5 patch 04 or later host:
 
  1. Run this voma command to analyze the storage device:

    # voma -m ptbl -f check -d <device>

    Note: The ESXi 5.5 P04 or later host must have access to the device(s) in question.

    You see output similar to:

    Running Partition table checker version 0.1 in check mode
    Phase 1: Checking device for valid primary GPT
    Phase 2: Checking device for a valid backup GPT
    Phase 3: Checking device for valid MBR table
    Phase 4: Searching for valid file system headers
    Detected valid LVM headers at offset 2097152
    Detected VMFS file system (labeled:'ACME') with UUID:xxxxxxxx-yyyyyyyy-zzzz-aaaaaaaaaaaa, Version 5:60
    Newly formatted VMFS5 file system detected
    Disk should have a GPT partition table with VMFS partition, start sector : 2048, end sector : 4294967262

    The key information in the preceding output are:

    Detected valid LVM headers at offset 2097152
    Detected VMFS file system (labeled:'ACME') with UUID:xxxxxxxx-yyyyyyyy-zzzz-aaaaaaaaaaaa, Version 5:60

    Note: Before you proceed, ensure that VOMA has detected a filesystem. Also, ensure the returned value matches the expected label (name) and UUID (if known).

    The next important information is:

    Disk should have a GPT partition table with VMFS partition, start sector : 2048, end sector : 4294967262

    VOMA assumes the partition looks like the preceding partition. You can then use the preceding start / end sector values to build your partedUtil command. For details on using partedUtil, see Using the partedUtil command line utility on ESXi and ESX .
     
  2. Create the partedUtil command to recreate the missing partition table:
    For example, with the preceding information this is the partedUtil command you create:

    # partedUtil setptbl "<device>" gpt "1 2048 4294967262 AA31E02A400F11DB9590000C2911D1B8 0"

    This creates a partition on the specified device.
    NOTE: Using VOMA to fix partition table issues is not a standard practice. Partition issues are addressed only through partedUtil   . 
  3. Use the partedUtil getptbl command to confirm that the new partition table state is reflected:

    # partedUtil getptbl <device>

    gpt
    #### ### ## #######
    1 2048 4294967262 AA31E02A400F11DB9590000C2911D1B8 vmfs 0
     
  4. Rescan the storage subsystem to prompt ESXi to look for new filesystems. For details, see Performing a rescan of the storage on an ESX/ESXi host.


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