Understanding the factors that affect the maximum rate of exporting a VM to OVF

Products

• VMware vSphere ESXi

Issue/Introduction

Exporting a VM to OVF is slow, throttling to XX MB/s. Keep in mind that the maximum speed varies for each individual, and results may differ depending on various factors.

Resolution

 

Exporting a VM to OVF involves CPU and storage-intensive processes, including grain-by-grain reading, gzip compression, and HTTP transfer. Performance throttles are expected behavior and vary based on hardware, storage layout, and network conditions. Expecting performance equal to simple file-copy tests is not realistic due to this architectural overhead.

Functional Limitations

• No Resumable Exports: The OVF Tool does not support resuming interrupted exports. If a transfer fails, the entire process must be restarted.
• No Export Order Control: The tool processes disks based on internal logic. There is no supported parameter to dictate which virtual disk is exported first or last.

Recommended Alternatives for Large VMs

For environments requiring the transfer of multi-terabyte VMs or those where export reliability and efficiency are critical, the following alternatives are recommended:

• vSphere Content Library: This is the preferred method for large-scale VM transfers. It is designed to handle high-volume environments more reliably than the OVF Tool and minimizes the risk of timeout-related failures.