User is not able to use the full expanded PMEM capacity.

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:
Whenever an NVDIMM is expanded on a Windows VM, the guest OS does not see the actual size.

Environment

VMware vSphere ESXi 7.0.1

Cause

To make expand PMEM work in Windows, user must use None Atomicity mode, but default mode is BTT mode.

Resolution

Currently there is no resolution.

Workaround:
Follow the below mentioned steps:

1. In Windows, add regkey to pmemdisk
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\pmem
   i. Value (REG_DWORD)      DefaultAtomicityMode      1

2. Power off VM, create pmem disk and make sure it is in None Atomicity mode.
   This can be confirmed by command "Get-PmemDisk"

3. Initialize pmemdisk and Create NTFS using "disk management" tool in Windows.

4. Double confirm the disk is in None Atomicity mode.

5. Expand the NVDIMM size from vSphere UI.

6. In Windows, use diskpart.exe to extend the disk. Here is an example.

DISKPART> list volume

Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0   D         CENA_X64FRE UDF DVD-ROM 4484 MB Healthy
Volume 1   E         New Volume NTFS Partition 2030 MB Healthy
Volume 2   C         NTFS Partition 95 GB Healthy Boot
Volume 3             FAT32 Partition 100 MB Healthy System
Volume 4             NTFS Partition 541 MB Healthy Hidden

DISKPART> select volume 1

Volume 1 is the selected volume.

DISKPART> extend

DiskPart successfully extended the volume.

DISKPART> list volume

  Volume ### Ltr Label Fs Type Size Status Info
  ---------- --- ----------- ----- ---------- ------- --------- --------
  Volume 0   D CENA_X64FRE UDF DVD-ROM 4484 MB Healthy
* Volume 1   E New Volume NTFS Partition 3055 MB Healthy
  Volume 2   C NTFS Partition 95 GB Healthy Boot
  Volume 3     FAT32 Partition 100 MB Healthy System
  Volume 4     NTFS Partition 541 MB Healthy Hidden