Error Code 64: The specified network name is no longer available.

[JohnLCS]

Good day,

We're attempting to synchronize files between 2 Windows Server 2019 Domain Controllers running on VMWare vSphere (ESXi) v6.7. The two servers are in different locations, connected via VPN. The bottlenecks we're aware of are VPN encryption and upstream bandwidth (50M up) at one of the sites. We've made several performance improvements by adjusting settings related to networking within the Windows Server VM's network stack. We can easily achieve 40Mbit file transfers inside Windows.

The scanning (with 8 threads in Donation Edition) is pretty fast. 198k files compare in about 60 seconds. This is up from 20 minutes before we made the performance improvements. We are however still receiving the following errors:

Cannot create directory "\\UNCpath\"
Error Code 64: The specified network name is no longer available. [CreateDirectory]

Cannot copy file "\\UNCPath"
Error Code 64: The specified network name is no longer available. [CopyFileEx]

I haven't encountered this before with FFS, so I'm not sure where to go from here. This is the error that we were getting prior to the network optimizations. This lead us to improve performance since file operations were taking a really long time, even just using the Windows GUI. Once we corrected those, files copy normally. I assumed that would fix this error, but it appears not. I've tried running FFS as an administrator also, and that didn't change the behavior.

If there is additional testing that I can do, or if you want me to send logs or other files I'm happy to. Thank you for reading.

-JohnLCS