I have problem and don't know how resolve it. I need sometimes to copy files around 80-100MB between two sites with Mikrotik routers on both side. On Main site I have fiber 100mbit/s and on remote fiber 50mbit/s. When I start copy files using SMB protocol between shared folder from main site to shared folder remote site, it go to about 70-80% then in torch I see that speed is going down until 0 and then fail. Windows then give me error "The specified network name is no longer available." During transfer file I have open CMD windows with ping to destination computer and pings working all the time even transfer is cancelled. I have this problem no matter what operating system I use to copy from/to.
When I compress files to 20-40MB or choose any other smaller file ~ 20-40MB then they are transferred without issues. Between sites I have openvpn tunnel. I do not have any Queues on both sides.
Do you have any idea how could I troubleshoot this?

Hi Zuku

I had this issue with openvpn linux server windows client for backups (big ones several hundred meg) and synchronisation..

Have you tried a workaround eg rsync, allows partials, restart and compression but learn the windows switches (time stamps are different to unix and osx). Ports to windows are ready to use out of the box, solved my problem.. There are gui wrappers for those allergic to command lines..

regards
Chris,

I'd suggest checking MTU. Try lowering it some on each side. PMTUD should take care of this, but it may either not be enabled, or ICMP packet too big messages may not be able to reach the source host. I'll admit it doesn't seem too likely since you get to 80% and compressed large files still make it through, but it's easy to try.

SMB over the web is hideous. Latency will affect the performance massively. If you can you might be better trying to get an FTP or SFTP up and attack it that way.