Mac OS X Speed up Samba File Copy Speeds - Powered By Kayako SupportSuite

08 Sep 2010

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	Mac OS X Speed up Samba File Copy Speeds

Solution I've had absolutely horrible speeds while copying files from my Samba server, and it was starting to drive me nuts. Well, for those of you that experience this, there is a very easy fix.

Simply add the following line to /etc/sysctl.conf (this is the file that is read on boot to set sysctl variables):

net.inet.tcp.delayed_ack=0

This simply tells the TCP stack in the kernel to not delay packet acks. The reason the slow down occurs is that when you are not sending anything to the Samba server, but attempting to copy a huge file from it, your computer will queue up a bunch of acks, and then send them after a bit. This causes the Samba server to stop sending files as fast, and then you end up going only a few kilobytes per second.

If you want instant gratification, open up a terminal window and sudo su -. Then, paste this in:
sysctl -w net.inet.tcp.delayed_ack=0
This is the same as what is in /etc/sysctl.conf, but the setting will be lost after a reboot. Enjoy!

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17 Nov 2008 01:47 PM