Friday, December 27, 2013

I don't even

Look, to some extent I like Mac OS X. It's a UNIX, it has some software (though, very little compared to linux). I like the objective-c language, and developing for iOS is a huge buzz with high salaries. Oh, and it has DTrace. Other than that I don't really have a reason to like it.

Some things about this OS are undocumented and badly broken. Take file system management for example. Tonight I looked at the free disk space and found out that some entity named "Backups" occupied 40GB. Turns out it's Time Machine's local snapshots. The proper way to get rid of them would be to disable automatic backups in Time Machine. One can also disable local snapshots from command line like:

tmutil disablelocal
And this is where I've effed up. This did not remove any space. So, I went ahead and removed the ".MobileBackups" and "Backups.backupdb" folders. NEVER EVER FUCKING DO IT. The thing is that Time Machine, according to some reports, creates hard links to directories (sic!), and now I just lost those 40 gigs - they ain't showing up in "du -s", but they show up as "Others" in the disk space info. Sooo. next time, use the "tmutil delete" to delete those directories.

Ok, I've re-enabled the snapshots with "tmutil enablellocal" and disabled them with the GUI. After that, I opened the Disk Utility and clicked "Verify Disk". It reported that the root FS was corrupted, I had to reboot to the recovery image and run the "Disk Repair". It's really confusing that OS X can perform live fsck (it just freezes all IO operations until fsck is done) but can't repair a live FS.

And a bonus picture for you. In the process I've unplugged my USB disk several times without unmounting and the FS got corrupted. This is what I got for trying to repair it.

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