Comments on: Ten Myths of Leopard: 6 Time Machine Eats Hard Drives!

By: Bobson

Bobson — Wed, 07 Nov 2007 11:56:11 +0000

lmasanti - that’s easy. Just go into your Time Machine drive, pick the folder for the backup you wish to off-site, and drag/burn it as appropriate. Alternatively, plug in a new drive and set it as your time machine drive for one backup, then switch back and take that off site.

By: lmasanti

lmasanti — Wed, 07 Nov 2007 01:12:28 +0000

The one thing I think it is missing is the ability to do a “full off-device backup”, likt to dvd or other disk, to be put on other location.

By: larryv

larryv — Tue, 06 Nov 2007 23:06:34 +0000

I, likewise, have never successfully found anything using Windows XP search. Ever.

By: elppa

elppa — Tue, 06 Nov 2007 19:02:00 +0000

Windows Vista search can be quite snappy.

I have yet to have any success searching for anything in XP though.

By: Bobson

Bobson — Tue, 06 Nov 2007 11:52:35 +0000

I’m surprised you didn’t mention what I think is the best space-saving feature of Time Machine: hard links. Have a huge number of copies of your entire drive… and yet have it take up a minimal amount of actual space, because not many files change.

If I leave my computer sitting untouched all day while I’m out of the house, it still generates its hourly backups, but it won’t ever fill up the drive. Just one less way it can “eat up” my drive!

By: lowededwookie

lowededwookie — Tue, 06 Nov 2007 08:20:38 +0000

Who are these muppets that spew this bollocks?

Clearly they have no idea about backups.

When I was doing onsite support I was in charge of backups. I would have to do a daily backup which was on a set of 5 tapes on a two week rotation. Then there was a monthly tape which was on a 12 monthly rotation. Finally there was one large one that was a yearly backup which was never rotated and had to be kept for 7 years.

The fact that Time Machine does the same thing but on a single drive is both time saving and fire and forget but reliable. There were times when I forgot to do a backup or something went wrong with the tape or system.

Very little can go wrong with Time Machine because the routine is hourly, daily, weekly, monthly. How is this difficult to understand?

My only gripe would be that you can’t set another drive for monthly backups.

By: larryv

larryv — Tue, 06 Nov 2007 06:53:52 +0000

It certainly is silly to think that Time Machine will gobble up your hard drives one after another, but from what I understand, it does it in a way even more clever than you describe here.

Unless I’m mistaken, Time Machine doesn’t really chow up space at all, and it doesn’t take 24 hours to “level off”—it does so after the first backup! When Time Machine first begins working with a particular external drive, it makes a complete backup of the entire system. Then, every hour, it only copies those files which have changed since the the last hourly backup. However, it maintains a “complete” record for each hourly backup by creating hard links to data that has not changed.

For example, after 6 hourly backups, a file that does not change very often (e.g., /System/Library/Filesystems/zfs.fs) will have 6 hard links associated with it, while its data will only take up 160 KB, not 960 KB. On the other hand, a 1 MB file that has changed more frequently than ever hour (a report, say) will take up 6 MB.

A more technical description can be found here:
http://arstechnica.com/reviews/os/mac-os-x-10-5.ars/14