Time Machine And "Unsupported" Disks

There are some tips floating around that tell you how to reconfigure Time Machine to use "unsupported" disks for backup, including USB drives attached to Apple's AirPort Extreme.

Don't use them.

I know some people have tried changing the settings as indicated and have said they've had no problems, but to those people I just have to ask: How do you know?

You see, the nature of the error means that you're not going to know about any problems you may or may not have until you go back and actually try to use the corrupted file in question.

By which time it may be too late.

And yes, I've tried it, and yes it seems to work. But note the emphasis.

I'd have to do a byte-by-byte comparison to be sure, and even if everything matched up all I'd know would be that it had worked that time.

Time Machine does backups up every hour. Every day. Going to check all of them?

At any rate, a fix from Apple is forthcoming. I advise you to wait for it.

And no, I'm not giving you a link to this one.

[UPDATE]

This problem has been fixed. See: Time Machine And The AirPort Extreme: What You Need To Know

Comments

[Mike]

Okay, so I ran the terminal command before I read all of these dire warnings. Normally, I don't use terminal because I don't know what I'm doing there. How do I undo this command and put things back to normal?

[Frost]

Mike: If you refer to that same terminal command I found ("defaults write [...blablabla...] 1"), my guess would be to run the same command again, but ending it with 0 (zero) instead of 1 (one).
I'm not sure about this one though, since I haven't actually tried it myself (haven't tried the original command either, for that matter), but I think that should solve your problem

[+ simonas]

Confirmation. To undo the hack, use the same string, but end it with a 0 rather then 1. Network drives don't show up anymore.

[Alex]

Does this mean that Time Machine does not verify backups that it's just written?

The "verify backup after writing" options available any proper backup software exist to protect the user from broken tapes (dodgey media, dirty heads, worn out tape drives, yadda yadda).

It wouldn't surprise me to find that the real reason Time Machine won't talk to AirDisk is simply that USB drives vary so widely in quality, and are damned slow. The Time Capsule has a directly-connected drive, which means latency is reduced - and it's a component that Apple has direct control over.