Cannot place any Virtual disk file whose size is not an integral multiple of 1024KB (1MB) on the VVOL Datastore

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:
In the environment where the VVOL Datastore is used, you see these symptoms:

• When a virtual machine uses a virtual disk whose size is not an integral multiple of 1024 KB (1MB), Storage vMotion or cold migration to the VVOL Datastore fails.

You see an error similar to:

Error caused by file filename.vmdk.

• A virtual disk file whose size is not an integral multiple of 1024 KB (1MB) cannot be created on the VVOL Datastore by using vmkfstools command.

You see entries similar to below in hostd.log :

Creating disk '<Virtual disk name>' and zeroing it out...
OBJLIB-VVOLOBJ : VVolObjCheckSize: Requested size (#######) is not a MB multiple.
OBJLIB-VVOLOBJ : VVolObjDetermineSizeInMB: Requested size (#######) is not a MB multiple.
Failed to create virtual disk: The requested size is not a multiple of 1MB (#########).

 

Environment

VMware vSphere ESXi 6.0
VMware vSphere ESXi 7.0
VMware vSphere ESXi 6.7
VMware vSphere ESXi 6.5

VMware vSphere ESXi 8.x

Cause

The size of a virtual volume must be a multiple of 1 MB, with a minimum size of 1 MB. As a result, all virtual disks that you provision on a Virtual Volumes datastore must be an even multiple of 1 MB. If the virtual disk you migrate to the Virtual Volumes datastore is not an even multiple of 1 MB, extend the disk to the nearest even multiple of 1 MB.

Note: 
This issue is also observed when Virtual Machine files are migrated using Storage vMotion, from NFS/VMFS/vSAN datastores to vVol Datastores. 
You can use the Virtual Volumes datastores with traditional VMFS and NFS datastores and with vSAN. Virtual Machines created on NFS/VMFS/vSAN Datatores do not have the limitation of defining the virtual disk to be an exact multiple of 1 MB.

Resolution

To resolve this issue, create a virtual disk whose size is an integral multiple of 1024 KB (1MB) or extend the existing VMDK to a size in multiples of 1024 KB.

By using vSphere Web Client, you can create only a virtual disk whose size is an integral multiple of 1024 KB (1MB) or extend the same.

 

To identify all the vmdks which are impacted by the issue in the environment, follow the steps below:

• Log in to the ESXi shell and navigate to the virtual machine's directory.
• To identify VMDKs that are not MB aligned, run the following command:

  for i in *.vmdk; do case "$i" in *-flat.vmdk|*-delta.vmdk|*-ses*) continue;; esac; R=$(grep "RW " "$i" | awk '{print ($2*512)%1048576}'); if [ -n "$R" ] && [ "$R" -ne 0 ]; then echo "$i is not MB aligned (Remainder: $R bytes)"; fi; done

• If any disks are returned, use the vSphere Client to extend the identified VMDK to the nearest whole MB integer

Note: This is a limitation on Virtual Volumes Datastores. [Virtual Volumes Datastores].

Additional Information

Virtual Volume Concepts