Microsoft FSLogix with Cloud Cache providers using vSAN FS does not replicate local profile

Products

• VMware vSAN

Issue/Introduction

Profile VHDX files configured to use vSAN File Shares as CloudCache provider(s) are smaller than the local profile (local proxy file). Also, VHDX files located on vSAN GS do not seem to grow over time. 

Environment

VMware vSAN 7.0.x

Cause

This issue is a limitation of 9p protocol which does not support fallocate 

[2022/10/19 09:54:01.018198, 2] ../../source3/smbd/smb2_ioctl_filesys.c:508(fsctl_zero_data)
  zero-data fallocate(0x3) failed: Invalid argument
[2022/10/19 09:54:01.018398, 3] ../../source3/smbd/smb2_server.c:3275(smbd_smb2_request_error_ex)
  smbd_smb2_request_error_ex: smbd_smb2_request_error_ex: idx[1] status[NT_STATUS_INVALID_PARAMETER] || at ../../source3/smbd/smb2_ioctl.c:312
[2022/10/19 09:54:01.020193, 2] ../../source3/lib/system.c:539(sys_fallocate)
  unmapped fallocate flags: 2
[2022/10/19 09:54:01.020233, 2] ../../source3/smbd/smb2_ioctl_filesys.c:508(fsctl_zero_data)
  zero-data fallocate(0x3) failed: Invalid argument
[2022/10/19 09:54:01.020255, 3] ../../source3/smbd/smb2_server.c:3275(smbd_smb2_request_error_ex)
  smbd_smb2_request_error_ex: smbd_smb2_request_error_ex: idx[1] status[NT_STATUS_INVALID_PARAMETER] || at ../../source3/smbd/smb2_ioctl.c:312

Resolution

The use of Microsoft FSLogix Cloud Cache with vSAN FS is not supported.