OS X Mavericks network timeouts
Initially when Mavericks hit the app store, i was eager to try it out, so started with upgrading my Mac mini from 10.8.5 to 10.9.
Installation was successful, and I started testing smb2 out, as this was the main reason for the upgrade, however i found that it was terrible slow – copying 1GB would take around an hour..
Started a ping towards different IP addresses on different vlans, and noticed that pinging when routing was needed would give me timeouts of 5 seconds every 30-45 seconds..
Found this thread on the apple forums: https://discussions.apple.com/thread/5483424?tstart=0
And this was exactly my problem, my network core consists of 2 Cisco Nexus 5548UP with some 2248’s connected, they are configured with vPC and HSRP, and in Mavericks arp is unicasted which causes mac addressed to flap between the 2 5548’s.
So the solution to the problem:
sudo sysctl -w net.link.ether.inet.arp_unicast_lim=0
or set it in the /etc/sysctl.conf
sudo sh -c 'echo "net.link.ether.inet.arp_
unicast_lim=0" >> /private/etc/sysctl.conf'
which makes arp broadcasted and not unicasted.