When I copy a large file (100+mb) to a remote server using scp it slows down from 1 mb/s to 100 kb/s and downward and then stalls. The same happens when I try to use rsync.

I've been able to transfer huge files using SCP before between these two machines.. But for the past week I cannot seem to send anything.. Nothing really changed as far as I can recall.

I've checked both computers for free space and cpu/mem usage. They look fine.

Any help please?

  • 1
    Need more information. --What does the network topology look like? How are the NICs configured? Did you get error messages? Logs?
    – xguru
    Aug 18, 2016 at 18:11
  • 1
    In addition to xguru's question around network topology, are you travering a VPN or GRE tunnel? Are you looking for tcp stats with netstat -s? Here is a function I used in my shell to watch tcp stats change as I transfer files. Look for congestion, retransmissions, loss events, etc.
    – Aaron
    Aug 18, 2016 at 18:57
  • If it's going through a home router you're probably running it out of ram due to the difference between your LAN speed and your internet speed. Both rsync and scp have options to limit the speed of the transfer, check their man pages. Also if you've messed around with your TCP settings recently, this is what your TCP Window values are supposed to prevent. Aug 18, 2016 at 21:26


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