[CentOS] Fail Transfer of Large Files

Michael D. Berger m_d_berger_1900 at yahoo.com
Sat Nov 20 22:28:11 EST 2010


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.



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