Time Machine is SLOW

[pttymuth]

Hi All,

This is the first time I've encountered this problem. I have a Time machine backup thats been happening since yesterday morning. Just under 80 GB is being backed up. After 30-ish hours, only 10 GB has been backed up. Usually Time Machine backups happen at a decent speed with the other OS X machines.

My current FreeNAS server has 32 GB of RAM, 8 cores running close to 4 GHz, and is connected to the OS X machine with a Gigabit connection. These specs lead me to believe that there aren't any hardware bottlenecks on the FreeNAS server. The OS X machine also has decent hardware specs. The only network activity either machine is engaged in is the single Time Machine backup.

I saw some strange activity while inspecting the tcpdump output on both machines. During a Time Machine backup I'd expect to see lots of constant traffic between the FreeNAS machine and the OS X machine. Instead the traffic seems to 'stutter.' The FreeNAS tcpdump output will appear very busy for several seconds, then halt for a several more seconds, then start again with for several seconds, then start again, etc. Whenever the tcpdump output stops on the FreeNAS machine, it's always on a zero-length packet logged by tcpdump. The OS X tcpdump output is similar with one difference: where the tcpdump output on the FreeNAS machine appears to stop, the OS X machine's tcpdump output shows many zero-length packets being transmitted to the FreeNAS machine.

Below is a sample of one of the zero-length packets shown in the FreeNAS machine's tcpdump output.

Code:

15:18:11.648353 IP 192.168.0.153.50015 > 192.168.0.129.afpovertcp: Flags [.], ack 8091, win 13821, options [nop,nop,TS val 1002836124 ecr 3383317847], length 0
15:18:12.652379 IP 192.168.0.153.50015 > 192.168.0.129.afpovertcp: Flags [P.], ack 8091, win 13825, options [nop,nop,TS val 1002837126 ecr 3383317847], length 22                                                                             
15:18:12.652389 IP 192.168.0.129.afpovertcp > 192.168.0.153.50015: Flags [.], ack 1134150, win 28803, options [nop,nop,TS val 3383318852 ecr 1002837126], length 0
15:18:12.652463 IP 192.168.0.129.afpovertcp > 192.168.0.153.50015: Flags [P.], ack 1134150, win 28806, options [nop,nop,TS val 3383318852 ecr 1002837126], length 50
15:18:12.652524 IP 192.168.0.153.50015 > 192.168.0.129.afpovertcp: Flags [.], ack 8141, win 13821, options [nop,nop,TS val 1002837126 ecr 3383318852], length 0

Reading packets out of tcpdump isn't something I'm particularly good at. While I'm noticing a pattern here, I've no clue if it's something worth looking at. I'm hoping somone on here is familiar with it.

There is a chance that the user posting this thread encountered the same problem:
http://forums.freenas.org/threads/time-machine-super-slow-backup.9914/

 

[fracai]

Anything in the system logs on your Mac? Open Console.app and filter by "backupd".

 

[pttymuth]

Thanks fracai!

After delving into the output of Console.app I realized there was something strange going on with my NIC driver. I went ahead and reinstalled the driver and the backup seems to be working fine now.