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Time Capsule first impressions

I got to play with my new Apple Time Capsule over the weekend, and I have some mixed feelings about it.

The good news is that for simple configurations, the setup is entirely automagic. The Airport Utility is smart enough to snarf your wireless settings, including WPA passphrases from your Keychain, and set up the Time Capsule to replace your existing access point. There are also wizard-driven config options for adding it to your wired network via ethernet, and via WDS to an existing wireless network.

The bad news is that as expected, anything more complex is a battle. Like with the Airport Extreme (the Time Capsule really is just an Airport Extreme with a built-in SATA disk), there is no way to disable DHCP if you want NAT. My workaround was to create a single IP DHCP pool, and 'reserve' it for a DHCP ID that I don't use on my network. This allows me to continue using the awesome Nominum DCS running on a Linux box as my DHCP server.

The wireless seems to be a little flaky. I noticed frequent drops in wireless on my Macbook that seem correlated to WPA key rotation on the Time Capsule. There is a key rotation interval configuration option in the Airport Utility, but it seems to be ignored. This could be a deal-breaker for me since my old trusty $50 Linksys WRT54G running OpenWRT does a much more reliable job as an AP (albeit without 802.11n).

As a NAS, the Time Capsule should work great in an all-MacOS environment. I did some light benchmarking with the AJA KONA System Test, a standard benchmarking utility from the digital video production industry. It does throughput tests on a range of file size reads and writes. When I get the time, I plan to hit the Time Capsule with Bonnie. I connected my Macbook directly to a Gigabit Ethernet port on the Time Capsule. For sequential reads/writes at least, the Time Capsule seems to do a decent job.

Here are the results when mounting the Time Capsule via Appleshare:

  MB       MB/sec
           Read      Write      
128.0      15.0      10.4      
256.0      15.0      10.6      
512.0      15.0      9.9      
1024.0     15.0      9.3      
2048.0     14.7      8.8      
4096.0     14.9      8.7

Here are the results when mounting the Time Capsule via CIFS (Windows file sharing):

  MB       MB/sec
           Read      Write      
128.0      11.1      8.6      
256.0      11.8      9.2      
512.0      12.5      9.0      
1024.0     12.4      9.3      
2048.0     12.5      9.1      
4096.0     12.3      9.2    

Now the really bad news. I mounted the Time Capsule via CIFS on my Fedora Core 5 machine, and tried backing it up with rsync. No matter what I tried, the rsync would stall after about 8000 io operations. Opening another shell and simply trying an 'ls' on the cifs-mounted directory would fail with a 'Host is down' error. Trying to SMB mount it from my Macbook at that point would simply time out.

It gets worse- once the Time Capsule is in this state, restarting it from the Airport Utility would fail. The Time Capsule's status LED would go orange before restarting, indicating an error condition. I don't know what the error is, since at that point, the Airport Utility no longer sees it; and the Time Capsule doesn't syslog any errors. The only way to fix it in this state is a hard power cycle.

Because of this, I suspect the problem lies with the Time Capsule, and not the CIFS support on my linux box. I will confirm and follow up with additional tests pushing the same rsync traffic from my Macbook cifs-mounting the Time Capsule.

Since I bought the Time Capsule to backup my home machines (Two Macbooks, a G4 Desktop, and my Linux box) and its failing to work for 1/4th of what I wanted it to do, I think that I should probably return it. $514 is a lot for a device that isn't working right. On the other hand, hopefully, maybe, Apple will fix the problem and release updated firmware. I could probably tolerate the SMB problem if the wireless was more solid. But I don't think that I can justify half a kilobuck for an AP/NAS that does neither job particularly well.



Mar. 4th, 2008 02:31 am (UTC)
Awww. I thought it was supposed to be good for Time Machine!


I've been alright, busy with stupid annoying things at work. I'm back on the west coast now, I should be here for a while (I hope!).


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