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Level 1

5 points

Time Machine Needs too much space, goes too slow?

I noticed recently that TM was taking a long time during backups, sometimes as long as 15-20 minutes to back up data in the MB, not GB, range. While doing some troubleshooting, I installed Time Machine Buddy. When I looked at the logs, I noticed stuff like this:

Found 145 files (91.5 MB) needing backup

5 GB required (including padding), 984.9 GB available

Copied 3434 files (8.8 MB) from volume myMac.

Using file event preflight for myMac

Will copy (305 bytes) from myMac

Found 14 files (305 bytes) needing backup

4.89 GB required (including padding), 984.89 GB available

So...to backup 91.5MB, it needs 5GB?

To backup 305 bytes (not KB, not MB -- bytes!), it needs 4.89GB?

What the heck? Could this be what's slowing down my backups -- some glitch making TM think it needs vastly more space than it actually needs?

iMac, OS X Mountain Lion (10.8.2)

Posted on Feb 13, 2013 10:59 AM

37 replies

Barry Lyga Author

Level 1

5 points

Mar 8, 2013 7:38 AM in response to Barry Lyga

Just adding to the thread, in case anyone can use this info...

It seems that when I am actually using the computer, TM is superslow. But if I'm not at the computer, when I check later, the TM backups seem to go much, much faster (like around a minute or two).

Pondini

Level 8

38,863 points

Mar 8, 2013 7:46 AM in response to Barry Lyga

That's rather odd. 😕

The only thing I can think of is, when you're using the Mac, are you doing anything unusual, especially running any 3rd-party apps that might be involved?

Whatever it is, sure seems to be related to the Event Store, but what that might be, I have no idea.

Barry Lyga Author

Level 1

5 points

Mar 12, 2013 6:33 AM in response to Pondini

Spent the past few days trying different combinations of apps and menulets activated/deactivated. Nothing seemes to make a difference. Bizarre!

Pondini

Level 8

38,863 points

Mar 12, 2013 10:59 AM in response to Barry Lyga

My sympathies. I'm completely out of even very-long-shot-from-the-weeds ideas. 😟

Barry Lyga Author

Level 1

5 points

May 10, 2013 2:36 PM in response to Pondini

Well, two months later and I have some new data, if anyone is still interested...

Bought a new backup drive (at last) and tried it. After the lengthy intial backup, backups to the new drive are on the order of 1.3-3 minutes. Much better than the old one!

I plugged the old one back in so that TM alternates backups. New drive: a couple of minutes. Old drive: up to half an hour.

So, it seems like the problem is the old drive. Or maybe it's some ON the old drive? I'm considering merging the two backups so that I don't lose the two years of backups on the old drives, but I'm concerned that doing so will move what slo-mo mojo is on the old drive to the new one.

Any thoughts appreciated. If not, I don't blame anyone! 🙂

Pondini

Level 8

38,863 points

May 10, 2013 3:55 PM in response to Barry Lyga

Barry Lyga wrote:

. . .

So, it seems like the problem is the old drive.

Does seem likely, doesn't it?

Unless it's connected with a different cable, and/or to a different port on your Mac. Those are always possibilities.

Or maybe it's some ON the old drive?

If Repair Disk shows it ok, then it's probably the drive beginning to fail. They don't actually crash very often any more, they just start needing more and more retries (read back to be sure it matches what was supposed to be written). I don't know how many retries drives do these days before reporting a problem, but if many writes require even two or three retries, things are going to slow wayyyyy down. Eventually, it will report an I/O error, and the process will fail or crash.

I'm considering merging the two backups so that I don't lose the two years of backups on the old drives, but I'm concerned that doing so will move what slo-mo mojo is on the old drive to the new one.

You can't "merge" two sets of backups. You could, however, create a separate partition and copy the old set to it. Then use the Browse... option to view them, per Time Machine - Frequently Asked Question #17.

Barry Lyga Author

Level 1

5 points

May 10, 2013 9:05 PM in response to Pondini

I'll try the different ports and cables just to be sure, but I really think it's just a dying drive.

As to merging: Yeah, I meant what you reference -- I was being quick and imprecise.

Time Machine Needs too much space, goes too slow?