Contributor
Contributor

Hot-Extending Large VMDKs in vSphere 6

Hi!

In VSphere 5.5 it is nessesary to turn off VM to extend large (>2TB) VMDK. Hot-Extending Large VMDKs in vSphere 5.5 - CormacHogan.com

Is it possible to extend lagre VMDK (>2TB) in VSphere 6 on working VM.

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3 Replies
Leadership
Leadership

Based on KB2058287, same restrictions apply for version 6, take a look: VMware KB: Support for virtual machine disks larger than 2 TB in VMware ESXi 5.5

Virtual machines with large capacity disks have these conditions and limitations:

  • The guest operating system must support large capacity virtual hard disks.
  • You can only move or clone disks that are greater than 2 TB to ESXi 5.5 hosts, or to clusters that have such hosts available.
  • The datastore format must be VMFS-5 or later, or an NFS volume on a Network Attached Storage (NAS) server.
  • vSphere Flash Read Cache supports a maximum hard disk size of 16 TB.
  • VMFS-3 volumes are not supported. You cannot move disks greater than 2 TB from a VMFS-5 datastore to a VMFS-3 datastore.
  • You cannot hot-extend a virtual disk if the capacity after extending the disk is equal to or greater than 2 TB. Only offline extension of GPT-partitioned disks beyond 2 TB is possible.
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Richardson Porto
Senior Infrastructure Specialist
LinkedIn: http://linkedin.com/in/richardsonporto
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Contributor
Contributor

I just tried this in our Vsphere 6 environment and the limitation still holds true.  You cannot hot-extend a disk to be larger than 2TB.

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VMware Employee
VMware Employee

Online/hot extension of 2TB+ VMDKs is not supported due to concerns about the GPT partition header update of a live virtual machine. Offline extension of VMDKs larger than 2 TB is supported.

Prior to ESXi 6.5, virtual disks could only be extended if their size was below 2TB when the VM was powered on. If the size of a VMDK was 2TB or larger, or the expand operation caused it to exceed 2TB, the hot extend operation would fail. This required administrators to typically shut down the virtual machine to expand it beyond 2TB. The behavior has been changed in vSphere 6.5 and hot extend no longer has this limitation.

It is important to note that this does not require VMFS-6 or Virtual Machine HW version 13 to work. VMFS-5 will also support this functionality as long as ESXi is version at 6.5

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