VMware Storage vMotion of thick provisioned virtual disks may perform better when using VMware vStorage APIs for Array Integration

Products

• VMware vSphere ESXi

Issue/Introduction

This article describes known behavior when using thin provisioned virtual disks with VAAI.

Symptoms:
You may experience one or more of these symptoms when using vStorage APIs for Array Integration (VAAI):

• Storage vMotion of thin provisioned virtual machines takes longer to complete than Lazy Zeroed Thick (LZT) disk virtual machines.
• LZT disk virtual machines complete first when the virtual machines are the same size.
• You see an increase in write and xcopy performance when converting thin provisioned virtual machines to LZT.
• Thin provisioned virtual machines generate a higher number of write commands on the array.
• Thin provisioned virtual machines generate a higher number of xcopy commands on the array.
  
  Note: The number of commands varies depending on your array vendor.

Environment

VMware vSphere ESXi 5.1
VMware vSphere ESXi 5.5

Resolution

This is by design, thin provisioned virtual machines have reduced performance compared to LZT provisioned virtual machines. Thin provisioned disks have reduced performance for writes and xcopies for LZT when using VAAI.

Additional Information

VAAI を使用している場合、VMware Storage vMotion のパフォーマンスはシンプロビジョニングよりシックプロビジョニングの仮想ディスクのほうがよい