Technology [Mac] Time Machine and corrupt files

[da8s0859q]

Long story short:

I use Time Machine with a Time Capsule for backups. Have since September '09.

A couple days ago, I wiped the drive in my MBP to clean out a lot of collected crap, used my Snow Leopard disc to reinstall 10.6.0, combo updated to 10.6.4, patched everything else as needed, used an ethernet cable to "hard" connect the laptop to the Time Capsule, and fired up Time Machine to selectively restore the stuff I wanted out of my home directory that was backed up.

Music, PDFs, med school stuff... all in all, approaching 100 GB of data.

As it turns out, some of what I pulled from those backups appears to be corrupted. Some MP3s don't play, some PDFs don't open because Preview.app doesn't recognize them as usable PDFs, that kind of garbage.

What's weird is that if I open the folder containing the corrupted file in Finder and use Time Machine to go back as far as the day after when that file was created in the first place, the file STILL appears as if it's corrupted -- the file icon doesn't refresh based on file type like it should, and restoring it is equally useless. I'm not entirely up to speed as far as how TM creates its backups, but it seems odd to think that every version of a given file is truly ****ed.

Bad bad news. Anyone have any thoughts on how I might get my stuff back in one piece?

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[deleted87716]

If the files are truly corrupted, I suspect you're SOL.

Most people I know who use Time Machine (not including me, BTW) also do periodic full bootable backups using something like Carbon Copy Cloner.

 

[1UP]

...but it seems odd to think that every version of a given file is truly ****ed...

I'm not familiar with the internals of TM, but for most automated backup systems this is exactly what will happen. If the first time it did the backup the file was crapped for some reason, and that reason persists for every subsequent backup, then all the future backups will also be crapped.

 

[da8s0859q]

I'm not familiar with the internals of TM, but for most automated backup systems this is exactly what will happen. If the first time it did the backup the file was crapped for some reason, and that reason persists for every subsequent backup, then all the future backups will also be crapped.

So you're saying that a bad initial backup of a good file can lead to all bad backups? Hrm, that's no good.

 

[1UP]

So you're saying that a bad initial backup of a good file can lead to all bad backups? Hrm, that's no good.

Somewhat. I'm basically saying that if the condition that lead to the initial backup being crap persist then all future backups will also be crap due to the continued presence of that initial condition.

In general, when it comes to backups, if the first backup of a file is crap, the last backup of the same file is crap, and you sample 2-3 backups in-between and they are also crap, there is a very high probability that all the backups of that file are crap and you are basically SOL. Checksums, data correction, and any other data recovery mechanisms won't help if the backup of the file was ******ed in the first place.

 

[TMP-SMX]

Yeah I had to restore from a backup before something went wrong with an update. Since there was a mismatch on the previous OS version and the updated OS backup nothing worked and I had to go to a backup from months previously. Moral of the story, backup before updating to a system you know worked fine and not after to a system you don't know is going to work. Also, if you are going to do something like a full restore just for the sake of doing it you are going to want a full clone to do it. That way you know everything is good.

TM looks for changes in files. It doesn't make a copy on files if nothing has changed since the first backup. That's how it saves space on backups. So if the first file was poorly copied it isn't going to work well.

 

[Phlame217]

Some timecapsules have also been recalled due to faulty hardware which could have caused the corruptions. Sucks, but as everyone has said, if the files are truly corrupt, you are SOL.

 

[da8s0859q]

Some timecapsules have also been recalled due to faulty hardware which could have caused the corruptions. Sucks, but as everyone has said, if the files are truly corrupt, you are SOL.

The last TC issue of note I read about was for units released between... February - June '08, was it? I picked up mine last summer; basic warranty expires next month, actually.

And yeah, it's not the first time that I've had problems with backups. Months ago, I copied over all the important stuff to an external HD, but it was... months ago. And that's assuming that none of that is corrupt too.

Better than haphazard file corruption though.

Ugh.

 

[Phlame217]

I use Western digital hard drives to back up, you can get a 2 TB on sale for 109.99 plus free shipping at the moment. I got the 1.5 TB for 99.99 a few weeks ago. They are the most reliable IMO.

I partitioned my 1.5tb for 3 partitions of .5 TB each, made one a storage, one a windows backup for windows 7 back up, and one a mac timecapsule back up. On the windows part i do full image backups (which includes the mac part since its a partitioned bootcamp windows sector) and that creates a redundant back up for emergencies of the mac part.

 

[da8s0859q]

I use Western digital hard drives to back up, you can get a 2 TB on sale for 109.99 plus free shipping at the moment. I got the 1.5 TB for 99.99 a few weeks ago. They are the most reliable IMO.

I partitioned my 1.5tb for 3 partitions of .5 TB each, made one a storage, one a windows backup for windows 7 back up, and one a mac timecapsule back up. On the windows part i do full image backups (which includes the mac part since its a partitioned bootcamp windows sector) and that creates a redundant back up for emergencies of the mac part.

Yep, I've got a 1 TB MyBook for much the same reason -- the last manual backup I did just in case TM decided to **** the bed on me (but ohhh no, I figured, surely that's not gonna randomly happen) was from a month and a half ago. But better to restore from that than go with the more recent one with random corrupted bits here and there.