Time Machine Backup Shockingly Slow

Discussion in 'OS X Mountain Lion (10.8)' started by JacaByte, Dec 16, 2012.

  1. JacaByte macrumors 6502

    Dec 26, 2009
    Hi, I recently installed a 500 GB Seagate Momentus XT in my 2010 MBP. Now I managed to get all my files onto the new hard drive via time machine after a clean install of Mountain Lion, the problem I'm now having is backing up the new hard drive to my time machine drive.

    It cleared off 260 GB off my 640 GB external drive, which I'm fine with, but now it's trying to write a 233 GB backup to the drive at about 10 Bytes per second. No joke, the counter increases by a kilobyte once about every two minutes. At this rate it will take more than a century to complete this backup, and I and the computer both will be long dead by the time that happens. This is just flat out ridiculous.

    Has anybody heard of this kind of behavior? I verified the time machine disk with disk utility and it passed, the only things I can think of are spotlight or disk fragmentation screwing up the works. Time Machine backups were perfectly fast in Mountain Lion and Sow Leopard before I upgraded the hard drive. If need be I can get a network AFB share running on a Linux box of mine to see if that backups my laptop any faster. If that worked I would try reformatting my time machine drive next.
  2. benwiggy macrumors 68020

    Jun 15, 2012
    1. How is the backup drive connected?
    2. Any relevant messages being left in Console utility? (anything with "backupd" may be useful.)
    3. Is this the same TM drive from which you restored everything? Is the old backup still there?

    You don't need to worry about disk fragmentation -- firstly, you've just moved everything to the new internal, so there won't be much fragmentation; and secondly, you don't need to worry about fragmentation on OS X anyway.
  3. JacaByte, Dec 16, 2012
    Last edited: Dec 16, 2012

    JacaByte thread starter macrumors 6502

    Dec 26, 2009
    1. USB 2.0 (A 22k modem powered with a hamster wheel)
    2. Some interesting stuff about the number of files it's copying;

    12/16/12 8:32:45.015 AM com.apple.backupd[1516]: Starting manual backup
    12/16/12 8:32:45.032 AM com.apple.backupd[1516]: Backing up to: /Volumes/Time Machine/Backups.backupdb
    12/16/12 8:32:45.608 AM com.apple.backupd[1516]: Event store UUIDs don't match for volume: Impulse
    12/16/12 8:32:46.865 AM com.apple.backupd[1516]: Deep event scan at path:/ reason:must scan subdirs|new event db|
    12/16/12 8:35:24.663 AM com.apple.backupd[1516]: Finished scan
    12/16/12 8:40:12.142 AM com.apple.backupd[1516]: Found 1061462 files (213.81 GB) needing backup
    12/16/12 8:40:12.382 AM com.apple.backupd[1516]: 257.98 GB required (including padding), 260.27 GB available
    12/16/12 9:32:45.941 AM com.apple.backupd[1516]: Copied 505.6 MB of 213.81 GB, 454574 of 1061462 items
    3. Yes and yes. Should it make a difference? This is technically the same system only with a new hard drive, I don't see why Time Machine would care.

    Anyway, 535 MB/52 min = 176 KBps, so I think it had a slew of tiny files to back up, which will take a long time with any connection when your source and target is a platter drive. I'll let it run and see what happens.
  4. benwiggy macrumors 68020

    Jun 15, 2012
    Yes, Time Machine knows and cares that your system is now on another disk.
    "Event store UUIDs don't match"

    It looks like TM is trying to make a new first backup of all your files. You should be able to look on the TM disk in Finder and see whether there are two sets of folders under "Backups.backupdb".
    It may also be getting confused because of the old files in its database.

    I think there are ways of reuniting the old backup with the new disk. There will be a page describing it somewhere, if it's possible.
    Otherwise, I would wipe the disk and start again.
  5. switon macrumors 6502a

    Sep 10, 2012
    RE: tmutil inheritbackup...

    Hi guys,

    If you look at the manpage documentation for tmutil you will see that you can attach your TM to the backup file from another computer. Or if you have simply moved your TM to a different disk, then you can use "tmutil" to switch to the new disk. The three commands I'd look into are "tmutil setdestination ...", "tmutil inheritbackup ..." and "tmutil associatedisk ...". Other "tmuitl" commands may also be useful, depending upon exactly what you need to accomplish.

  6. JacaByte, Dec 16, 2012
    Last edited: Dec 19, 2012

    JacaByte thread starter macrumors 6502

    Dec 26, 2009
    So the time machine managed to finish the back up in about 2 hours, but the backup was about 5 GB, not 233 GB.

    Hey thanks! I'll definitely take a look at these and see if there's a way to reunify this time machine with its computer.

    Update: I used a combination of tmutil associatedisk and tmutil inheritbackup to get everything on the time machine disk. I also deleted a backup file that never finished, (suffixed ".partial") that helped with the eternal "Cleaning up" message I was getting. Thanks for you help!

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