It was my ambition last night to set up a 300GB drive, hook it to the Airport Extreme in the office, and have a little backup action happening in an automated fashion.
The good old standby of Rsync was to be the weapon of choice. Given that my tower machine has a 90GB home folder (65GB of RAW images), I hooked the drive up directly over SATA and enjoyed 60MB/sec Rsync goodness. Good times.
Now to test with the Airport. Over wired ethernet, I see about 7MB/Sec out of the airport disk. So this should just cook right along for the small differential changes my home folder sees each day.
Hooked everything up, fired up rsync, then just stared. It made up the file list, and then just sat there. Forever.
So in the course of my checking out the problem, I discovered rsync was in fact checking out the files on the airport disk, just at 30K/Sec. Yeah. 30K. Checking attributes on 200,000 files at 30K/sec. This is not good. If I just grab a large file, everything is fine, and I get 7MB/sec. Small files? Horrible.
Just to make sure it wasn’t rsync doing something weird, I just tried copying my home folder back from the drive using the finder. Horrible. Tried hooking up another USB drive. Horrible. Tried the trick of turning off journaling on the drive. Horrible. Hooked up my laptop to the ethernet on the base station, mounted my tower’s home folder, rsync. Great speed.
So there’s an issue here. Looks like there’s just crazy access times for pulling files off an airport disk. If you’re copying only a couple of files, it’s no big deal if it takes 5 seconds for the airport disk to start the transfer on each file. When you’re doing it for 200000, it’s another story completely.
Now I could have a bad extreme here. So, do any of you out there have an airport extreme, and can replicate my testing? Just rsync over your home folder, and your /Applications folder. This should be enough files. Tell me what speeds you’re getting.