This issue has been extremely frustrating for us: when transferring a large VHD (virtual hard disk) file from a Windows 7 machine over the network to a physical Windows Server 2008 machine at our datacenter, the windows file transfer fails at 4 GB consistently. We have a direct 100 mbit connection from our main office to our data center.
When the transfer fails, the error message we receive is:
There is a problem accessing \\server-name\d$
Make sure you are connected to the network and try again.
It is only VHD files larger than 4 GB that fail. If we send any other file type, it works fine. If we zip the VHD, that also works. Moreover, we can send a VHD the other direction (from the data center to the main office) no problem. It is just VHD files in that direction.
Important notes:
- All partitions are NTFS!!
- There is no firewall between workstation and server
- We have tried disabling the antivirus on the workstation (no antivirus on server)
- We have tried transferring the file from a machine not on the domain
- We have tried transferring the file from a Ubuntu machine (still fails but at around 450MB instead of 4GB)
- Wireshark capture shows 40 DUP ACKs when transfer fails
- Xcopy and Robocopy (with restart flags) both fail (same point)
- FTP transfer fails at 4,14X,XXX,XXX bytes and cannot be restarted at that point
- We tried changing the file extension (stupid, but a last resort) to something other than vhd before sending it, but it still failed
- Connection is as follows: Dell Workstation (Main Office) -> Dell PowerConnect 5448 Managed Switch (MO) -> HP Procurve 2910al-24G Layer 3 Router (MO) -> 100Mb TLS link -> HP Procurve 2910al-24G Layer 3 Router (Data center) -> Dell PowerConnect 5448 Managed Switch (DC) -> Dell Server (DC)
So basically, it is JUST vhd files > 4GB, from our main office to our datacenter that fails. This all just doesn't add up... at this point I believe it is a issue with our network hardware settings, but I don't understand what the difference is between transferring a large VHD (which fails, at 4GB) and a large video file (which works always).