On Sat, 20 Nov 2010 18:17:23 -0600, Jay Leafey wrote:
Les Mikesell wrote:
[...]
This does ring a bell, but the circumstances were a bit different. In our case we were transferring large files between "home" and a remote site. SFTP/SCP transfers were stalling part-way through in an unpredictable manner. It turned out to be a bug in the selective acknowledgment functionality in the TCP stack. Short story, adding the following line to /etc/sysctl.conf fixed the issue:
net.ipv4.tcp_sack = 0
Of course, you can set it on-the-fly using the sysctl command:
sysctl -w net.ipv4.tcp_sack=0
It helped in our case, no way of telling if it will help you. As usual, your mileage may vary.
Googing around, I get the impression that disabling SACK might lead to other problems. Any thoughts on this?
Thanks, Mike.