Slow restore speeds on VDDK SAN transport mode with Commvault.
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Slow restore speeds on VDDK SAN transport mode with Commvault.

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Article ID: 371843

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Updated On:

Products

VMware vCenter Server

Issue/Introduction

  • Slow restore speed is observed using VDDK SAN transport mode.
  • Restores via SAN to the VMFS datastore and is hitting a ceiling of 400 MB/sec (This speed might be less and vary depending on customer setup) however restore to an NTFS LUN on the same array are faster.

 

Environment

  • VMware vSphere ESXi 6.x
  • VMware vSphere ESXi 7.x
  • VMware vSphere ESXi 8.x
  • VDDK 7.x
  • VDDK 8.x

Cause

VDDK on proxy server needs to communicate with VC (eventually the host where the target VM is registered on) for the info how to write the VMDK on VMFS blocks, then write the specific blocks on the target storage LUN device (without any filesystem layer).
This may introduce latency which seems an important factor for the restore speed.

Comparing the restore speed between VMFS and local NTFS is not advised as the NTFS can have optimization/cache the file IO before write to the flash storage.

 

 

Resolution

This is working as per the design.

 

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