VDDK uses san transport mode while backing up empty thin disks
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VDDK uses san transport mode while backing up empty thin disks

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Article ID: 339321

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

When backing up empty thin disks on VMFS datastore, VDDK uses san transport mode while the backup proxy does not have to access the LUN where the datastore locates.

For empty thin disks on VMFS datastore, VDDK tries with san mode firstly, then detects there are actually no storage blocks allocated, so VDDK can return all zero data for backup using SAN transport mode and avoid reading data from storage to improve the performance. 

Environment

VMware vSphere Data Protection 6.x

Resolution

There is no resolution for this issue as it causes no harm using SAN.
To work around this issue, make VDDK work under specific modes only, they pass modes to VixDiskLib_ConnectEx.