Failed to expand VMFS datastore - Cannot change the host configuration

Products

• VMware vSphere ESXi

Issue/Introduction

This article provides information on how to expand a local datastore which also happens to be the boot location of the ESXi host and other shared datastore. This is achieved by growing an existing VMFS Datastore in a Primary partition to fill the adjacent available space on the local boot device or the SAN scsi device.

Note: Datastore extents within Primary partitions on a Local or Boot storage device cannot be grown into adjacent space using the GUI and would need to be performed over the command line only. Prior to expanding the local datastore, ensure to verify and validate the following:

1. This article assumes that the underlying storage volume has already had its capacity increased from the hardware perspective, possibly by adding additional disk to a RAID set. For more information, engage your hardware vendor.
2. You cannot expand a datastore that is detected as a snapshot. For more information, see Troubleshooting LUNs detected as snapshot LUNs in vSphere.
3. A Datastore's partitions can only be grown into contiguous adjacent space on the disk. Ensure that the partitions in question are at the end of the disk.
   
   Warning: Be very careful to not overlap the any Primary and Logical partitions. This could result in data loss.

Symptoms:

• Expanding the local datastore or shared datastore on the ESXi host fails.
• You receive this error message similar to:
  
  Error: Failed to expand VMFS datastore datastore1 - Cannot change the host configuration.
  
  

Environment

VMware vSphere ESXi 7.0.x

VMware vSphere ESXi 8.0.x

Cause

This issue can be caused by the partition table on the underlying storage device not being resized to accommodate the increased capacity, or the filesystem not being extended to utilize the additional space on the LUN.

Resolution

Note: If you are expanding the shared datastore, jump to step 4 directly. 

 

On the ESXi host containing the local datastore you want to expand:

1. Open an SSH session and log in as root.
2. Identify the boot location of the ESXi host by running this command:
   
   ls -ltrh
   
   
    
3. Ensure that the symbolic link (symlink) is reflecting in a blue color.
   
   Note: If the symlink is a red color, this indicates connectivity issues to the underlying device and may not be readable or accessible.
    
4. Obtain the device identifier for the Datastore (For example: naa, mpx, eui, vml etc.) to be modified by running this command:
   
   vmkfstools -Ph -v10 bootbank
   or 
   vmkfstools -Ph -v10 /vmfs/volumes/<datastore name>
   
   For more information, see   Identifying disks when working with VMware ESXi.
   
   
   
   Note: The next steps use mpx.vmhbaX:CX:TX:LX as an example. Replace mpx.vmhbaX:CX:TX:LX with your device identifier that may begin differently. For example, naa or eui.
   
   
5. Record the amount of free disk space on the Datastore. For more information, see Investigating disk space on an ESXi host.
   
   
6. Equipped with the device identifier, identify the existing partitions on the device using the partedUtil command. For more information, see Using partedUtil command line disk partitioning utility on ESXi.
   
   partedUtil getptbl "/vmfs/devices/disks/mpx.vmhbaX:CX:TX:LX"
    
   The output should be like this indicating the 7 existing partitions, with VMFS occupying partition 3.
   
   
7. The highlighted field indicates the specifics for the VMFS partition.
   
   
   
   
8. Identify the desired ending sector for the VMFS datastores partition by executing the partedUtil getUsableSectors command:
   
   partedUtil getUsableSectors "/vmfs/devices/disks/mpx.vmhbaX:CX:TX:LX"
   
   34 16879000
   
   Resize the partition containing the target VMFS Datastore using the partedUtil resize command, specifying the existing starting sector of the partition and the desired ending sector:
   
   partedUtil resize "/vmfs/devices/disks/Device" PartitionNumber StartingSector NewEndingSector
   
   Note: The New Ending Sector here would be 1 sector less than output of the total usable sector obtained with the above command in the step 8.  New Ending sector > 16879000 - 1 = 16878999.
   
   For example, to resize the Primary partition 3, run this command:
   
   partedUtil resize "/vmfs/devices/disks/mpx.vmhbaX:CX:TX:LX" 3 10229760 16878999
   
   Note: If the partedUtil resize command fails with this error:
   
   The kernel was unable to re-read the partition table on /dev/Device (Device or resource busy).
   
   Reboot the ESXi host before proceeding with the next step.
   
   
9. Grow the VMFS Datastore in to the new space using the vmkfstools --growfs command, specifying the partition containing the target VMFS Datastore twice.
   
   vmkfstools --growfs "/vmfs/devices/disks/Device:partition" "/vmfs/devices/disks/Device:partition"
   
   For example:
   
   vmkfstools --growfs "/vmfs/devices/disks/mpx.vmhbaX:CX:TX:LX:3" "/vmfs/devices/disks/mpx.vmhbaX:CX:TX:LX:3"
10. Execute to perform a refresh of the VMFS volumes by running this command:
    
    vmkfstools -V
     
11. Validate that the size of the VMFS Datastore has increased by running this command:
    
    df -h
    
    Note: The size of the VMFS Datastore can be cached by hostd and vCenter Server, or any connected client. Click the Refresh button in the vSphere Client to update the Datastore capacity and usage.