Time Machine keeps doing full backups

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Time Machine keeps doing full backups

I have a TM drive (3TB) backing up 3 partitions (total of about 1.2TB) since Oct 2014. TM keeps doing strange things when I do something unrelated to TM. For instance, temporarily booting into Mavericks (I'm running 10.6.8) completely wrecks TM in 10.6.8 even if I've turned it off and physically disconnected the drive until I'm back in 10.6.8. I spent 2 months with Apple Support earlier this year trying to figure out how to get it to work in 10.6.8 again. I've reset TM (Pondini.org pages) numerous times. The most recent problem occurred when I tried to resize a partition on a mirror drive (excluded in TM). After I finished resizing, TM did a 600GB backup when there had been nothing changed on any of the 3 targets that TM usually backs up. I had to upgrade to a larger drive earlier this year because of this kind of behavior (2TB->3TB) and I reset the UUID of the new drive so it would continue where the 2TB drive left off using xattr and fsaclctl commands (this worked perfectly!). I'm slowly running out of space again. Does anybody understand why this is happening? More importantly, is there any way to delete a backup and not have TM redo it. I could easily delete the most recent backup but I suspect the next time TM does a backup, it will rebackup the 600GB. I suppose one solution is to buy yet another drive and reset the UUID but it doesn't solve the weird behavior problem. TM is an important historical archive but it's a royal pain!

Mac Pro, Mac OS X (10.6.8)

Posted on Dec 6, 2015 3:58 PM

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Answer 1

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Eric Root

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684,027 points

Dec 7, 2015 5:05 PM in response to jcgilbert1

Start with D3 & 4 in the 1st linked article.

Time Machine Troubleshooting

Time Machine Troubleshooting Problems

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Answer 2

jcgilbert1 Author

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Dec 8, 2015 10:57 PM in response to Eric Root

Thanks but I've already looked at those. It's unlikely that my mother board is bad given that this is the only abnormal issue I'm experiencing. In addition, I'm loath to throw parts at a problem without any hard data showing that the mother board is really the problem. It's actually not a FULL backup that TM is doing but some other large backup. I have noticed that running DiscWarrior on the disc to repair it (very seldom), causes TM to do a large backup (makes sense). TM has settled down for the time being although I lost about 300GB over the weekend after the repartitioning issue unrelated to any target discs. So I'm still at a loss to understand why TM would do such a large backup when I do something completely unrelated to it. I would really like to recoup some of that space but the Pondini pages indicate that when TM wants to do a full backup, there's really nothing I can do about it and once it's done, it's DONE. I have about 600GB left so I guess I'll just have to start buying a new 2-3TB drive every year or so. Disappointing and weird!

Is your name REALLY "root" or is that a nom de plume?

John

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Answer 3

Eric Root

Level 10

684,027 points

Dec 9, 2015 7:49 AM in response to jcgilbert1

You are welcome.

Is your name REALLY "root" or is that a nom de plume?

That is my last name.

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Answer 4

jcgilbert1 Author

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Dec 9, 2015 11:46 AM in response to Eric Root

With that name, you've clearly selected the right job 😉

BTW, I figured out why TM did that large backup. Pilot error: I somehow managed to opt out of one of the target discs in TM for a day. When I turned it back on, TM thought rightly that it was a new target disc and backed up the whole thing. Sigh. I guess I'll be more careful in the future.

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