Time Machine is doing very large backups

Question

Level 1

9 points

Time Machine is doing very large backups

Background: I bought new drive for Time Machine backup. First backup took about an hour and backed up about 80 GB (let's considered as good behaviour). Second backup was supposed to be above 70 GB (bad behaviour, bad) which could not really be the amount of data actually changed for the while between backups.

When i try manually run

tmutil compare

in iTerm, it returns a bit more sense making numbers

Glossary:

"supposed to be above" comes from estimated size in Time Machine preference pane
"actually 10 MB changed" comes from terminal
```
tmutil compare
```
result.

I think it's wrong it's backing up almost whole drive again. I know the backups consists of actual files and links to not changed files from previous backup. But the links should not consume same size as the linked file and according to free space after second backup the second backup is really consuming the space almost like first(full) backup (checked in disk utility)

I am using external USB drive

I tried:

reset Time Machine – http://pondini.org/TM/A4.html
reformat the backup partition on external drive
check both Macintosh HD and backup partition in Disk utility while being in recovery mode
check if both Macintosh HD and backup partition are GPT and Mac OS X Extended (Journaled)

Question: How can i prevent Time Machine to make so big backups when actually 10 MB changed?

MacBook Pro, OS X Mountain Lion (10.8.2)

Posted on Feb 14, 2013 12:01 PM

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Answer 1

Pondini

Level 8

38,863 points

Feb 14, 2013 5:29 PM in response to roolo

roolo wrote:

Background: I bought new drive for Time Machine backup. First backup took about an hour and backed up about 80 GB (let's considered as good behaviour). Second backup was supposed to be above 70 GB

Where did you get those two figures?

If in doubt, use the widget in #A1 of Time Machine - Troubleshooting to display the backup messages from your logs. Locate the two backups in question, then copy and post all the messages here.

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Answer 2

roolo Author

Level 1

9 points

Feb 14, 2013 11:30 PM in response to Pondini

1) Both the numbers are from Time Machine preference pane

2) From the screenshot it seems to me the widget is just reading logs so i attached backupd messages from Console

It looks terrible when i paste the log right here – https://gist.github.com/roolo/4958974

Apologies for it's just from yeasterday. I have no idea where did the old ones gone

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Answer 3

Linc Davis

Level 10

209,535 points

Feb 15, 2013 5:42 AM in response to roolo

You've run into a bug in CoreStorage that results in corrupt revision data. If you have saved versions of a document in any CoreStorage application, save them as files. Then delete the following directory and reboot:

/.DocumentRevisions-V100

If you need instructions on how to do that safely, ask. Try a backup.

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Answer 4

roolo Author

Level 1

9 points

Feb 15, 2013 4:00 PM in response to Linc Davis

Did not helped – i just deleted that folder since i don't have any versions a want to preserve

Is there some ticket for that or info page to start googling from?

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Answer 5

Linc Davis

Level 10

209,535 points

Feb 15, 2013 3:51 PM in response to roolo

I'm not sure what you mean. Did you delete the above directory and reboot, and if so, did you get the same error messages in the log?

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Answer 6

roolo Author

Level 1

9 points

Feb 15, 2013 4:05 PM in response to Linc Davis

What messages do you mean? And yes i've also restarted

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Answer 7

Linc Davis

Level 10

209,535 points

Feb 15, 2013 4:05 PM in response to roolo

kernel[0]: /SourceCache/AppleFSCompression_kexts/AppleFSCompression-49/Compressors/Datales s/compressorType5Kext.c:532: Error...

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Answer 8

roolo Author

Level 1

9 points

Feb 15, 2013 4:13 PM in response to Linc Davis

I'll give it one more try, because first time i just moved the directory

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Answer 9

roolo Author

Level 1

9 points

Feb 16, 2013 3:07 AM in response to Linc Davis

The message is gone, but it's still doing like 80 gigs bakcups

https://gist.github.com/roolo/4958974#file-backupd-2013-02-16-log

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Answer 10

roolo Author

Level 1

9 points

Feb 16, 2013 5:50 AM in response to roolo

I don't know if it helps, but i tried to make the backup in Safe mode. It was preparing long as **** and this was added into my Logs

Requesting maintenance wake [Backup Interval]: Sat Feb 16 14:18:36 2013 CET (approx)

I did not finnished the backup because i have to go. But it seemed to me everything in the Safe mode is slower

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Answer 11

Linc Davis

Level 10

209,535 points

Feb 16, 2013 9:58 AM in response to roolo

Delete the following directory in the same way as before:

/.fseventsd

Reboot and test. If there's no change, make another complete backup (not necessarily with Time Machine) to another external drive, then boot into Recovery and erase the startup volume. Restore from one of your backups.

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