StarWind Software

We have a lab environment that we are testing out Hyper-V on. FC SAN, two physical Hyper-V hosts with dual 10Gb NICs, two physical ESXi hosts with 10Gb NICs. When logged in and using the StarWind V2V converter on the Hyper-V host the NIC throughput never really goes above 500-600Mbit/sec. We've got jumbo frames configured across the board, switch ports, VMWare and hyper-v. Not sure if this is just how things are, due to single threading for the conversion or if I am missing something.

Welcome to StarWind Forum.
Throughput during conversion is not only about networks but also the destination and target storage.
StarWind V2V converter is a single-threaded app. Can be slow.
Wishing you a nice weekend.

JohnnyMc wrote: ↑

Fri Apr 17, 2026 1:05 pm

We have a lab environment that we are testing out Hyper-V on. FC SAN, two physical Hyper-V hosts with dual 10Gb NICs, two physical ESXi hosts with 10Gb NICs. When logged in and using the StarWind V2V converter on the Hyper-V host the NIC throughput never really goes above 500-600Mbit/sec. We've got jumbo frames configured across the board, switch ports, VMWare and hyper-v. Not sure if this is just how things are, due to single threading for the conversion or if I am missing something.

That’s pretty normal behavior for StarWind V2V Converter. It’s mostly single-threaded, so it won’t fully utilize a 10Gb connection even if your network is configured perfectly. The conversion process also adds disk I/O and format overhead, which further limits throughput, so 500–600 Mbit/sec is not unusual in this case.

Thing I have seen to help.

Source:
1. Increase read cache. (only helps short term)
2. Power off the VM
3. Execute during low off peak IOPS times (reminder on backups after hours could hit disk hard)

Destination:
1. Have a fast CPU higher single thread rating helps.
2. Use SSD is possible.
3. Increase write cache.
4. Use RAID10 on storage disk configuration if possible with 15K if spinning disks.

Wish list: what could happen with starwind now. Conversion of not just concurrent VM's, but concurrent disks.

Good point, yet the main bottleneck will be on the software side.

I've been doing my own testing here and appreciating this product very much thank you very much. I've hit 1.1Gbps so far and thought my bottleneck was the source ESXi host but am unsure.

@mr_v - how are you adjusting your caches? You talking on a hardware raid controller firmware or elsewhere?

Thanks for your update!