Hot Extend a VM disk on vVols

May 20, 2021

I had a customer ask about hot resizing (extend while VM is powered on) a VMDK for VM on a vVols datastore. They said they couldn't resize the disk and received an error. Turns out they had multi-writer enable on the disk.  To clarify, you can hot extend a VMDK on vVols if the disk is not shared and using either multi-writer or physical bus sharing. These are typically used for WSFC or Oracle clustered applications and hot-extend is not supported.

Enabling or disabling simultaneous write protection provided by VMFS using the multi-writer flag (1034165)

Other caveats that can prevent you from resizing a disk; VM has an active snapshot, VM HW version, or another vSphere process or change is active. If you can't extend past 2TB,  you may not have the supporting vSphere version. 

Here are mode details on hot extend past 2TB:

vSphere 6.5 Storage | VMware


Unable to Extend Your VM’s Disk Past 2TB Without Powering Off? (


Here's a quick video show how easy it is to hot extend a disk on a Windows 10 VM from 1TB to 2TB.

Hot extnd vVols 2TB

Hopefully this helps with hot-extend questions on vVols.




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Jason Massae

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Jason is the vVols and Core Storage Technical Marketing Architect for the HCIBU at VMware. Before joining VMware, he came from one of the largest flash and memory manufacturers in the world. There he architected and lead global teams in virtualization strategies for IT. Working with the storage business unit, he helped test and validate SSDs for VMware vSAN. Now his primary focus is vSphere vVols and Core Storage.