HotAdd Transport mode limitations with vSAN datastore

Products

• VMware vSphere ESXi

Issue/Introduction

The purpose of this article is to explain the limitations of VDDK backup using HotAdd transport mode with vSAN datastores.

Environment

VMware vSphere 6.5.x
VMware vSphere 6.7.x

Resolution

Cross filesystem type.
When the target machine has a vSAN datastore and the backup proxy is in
a non-vSAN datastore, HotAdd backup is not supported. There is no workaround.
This limitation goes back to vSphere 6.5 and has not been fixed by vSphere 8.0.

SEsparse snapshot issue.
When the target machine has a VMFS or NFS datastore and backup proxy in in
a vSAN datastore, HotAdd backup was not supported when there were SEsparse disks.
This issue existed in vSphere 6.x but was fixed in VDDK 7.0 for vSphere 7.0.

Note: On a VMFS 6 datastore, disk snapshots are created in SEsparse format.
On a VMFS 5 or NFS datastore, disks snapshots are created in SEsparse format,
and SEsparse format is used for disks larger than 2TB.