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"Backups" on Macintosh HD in Lion

jpetticrew

jpetticrew

macrumors 6502a
Original poster
May 13, 2009
782
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Texas
Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.0.2 Mobile/9A5259f Safari/6533.18.5)

I read that Time Machine does local backups when not connected to a hard drive. Where are they stored, and are they deleted after backing up to an external drive?
 
jpetticrew said:
Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.0.2 Mobile/9A5259f Safari/6533.18.5)

I read that Time Machine does local backups when not connected to a hard drive. Where are they stored, and are they deleted after backing up to an external drive?
Click to expand...
They are stored on /Volumes/Mobile Backups.
They are cleaned up after TM backs up.
 
bbogey said:
What are those what are in /.MobileBackups ?
I have there 19GB data even after TM has been finished backing up.
Click to expand...

My bad I left out the . , since the file is hidden.
Those are the local snapshots.
You can disable with sudo tmutil disablelocal and within a few minutes they will get deleted if you need the space. I don't know how often TM cleans them up though.
 
mrapplegate said:
My bad I left out the . , since the file is hidden.
Those are the local snapshots.
You can disable with sudo tmutil disablelocal and within a few minutes they will get deleted if you need the space. I don't know how often TM cleans them up though.
Click to expand...

The folder is in root /
There is also /Volumes/Mobile Backups without the '.', it's mounted from localhost: and some hash value.
Seems the folders inside are the same.

Anyone knows how much it fills up the disk? Or when TM cleans them up? It's not good to fill up the disc totally, it slows down the disk, especially when using SSD drives.

When checking disk usage with df -h, OSX disc usage has increased from 50GB to over 70GB, and now my 120GB SSD is 70% full. With SL it was in 50%

Finder stats bar shows 56GB for system drive, so it does not include the Mobilebackups in the disk usage.
 
Ok I turned off the local mobile backups with "sudo tmutil disablelocal"

before

$ df -h
Filesystem Size Used Avail Capacity Mounted on
/dev/disk0s2 111Gi 77Gi 34Gi 70% /

after

/dev/disk0s2 111Gi 58Gi 53Gi 53% /


From man tmutil:

disablelocal
Turn off local Time Machine snapshots and trigger automatic cleanup of accumulated local snapshot data. Requires root privileges.​
 
Does the '.Mobile Backups' directory get removed once TM catches up on its' backups? On my system I can't find '/Volumes/.Mobile Backups'
 
When Mobile backups are enabled, following folder and mount exists

/.MobileBackups/
/Volumes/MobileBackups
 
basher said:
Does the '.Mobile Backups' directory get removed once TM catches up on its' backups? On my system I can't find '/Volumes/.Mobile Backups'
Click to expand...

I don't know the time frame or even the limit. There was a nasty bug in the early previews that allowed the local backups to grow and grow. Now they seem to be under control since developer preview 4 . What exactly these limits are, I don't know. You lost about 20GB and that seems like a lot to have stored. I would keep it off if not needed or if needed on and keep an eye on it daily.
 
Figured out why I don't have the .Mobile directory. I'm on a desktop system. Guess I can fiddle with tmutil if I want the same functionality on my iMac. For the moment I think I'll forgo it.
 
bbogey said:
What are those what are in /.MobileBackups ?
I have there 19GB data even after TM has been finished backing up.
Click to expand...

I am seeing the same thing on my MacBook Pro. The /.MobileBackups directory contains 19GB of data, but this data isn't being copied back to my Time Machine volume (network drive) when it is available. The reviews I've read also mention this syncing back to the Time Machine volume, but it doesn't appear to be working on my machine.

I've also noticed that local backups are being made when my Time Machine volume is available, sometimes even at the same time as when a "normal" Time Machine backup is being made. As far as I've understood, local backups should only be made when the the Time Machine volume isn't available.

Is anyone else seeing this behaviour?
 
Hope this helps.

If you don't want local snapshots, you can disable them with the command line tool tmutil. In Terminal:

$ sudo tmutil disablelocal

Then write your password. Depends on HD speed and backup size, it will take a couple of minutes to delete local snapshots.
(I have a Sata III SSD and it took almost 10min. to delete 20gb of local backups.)
 
JB360 said:
I am seeing the same thing on my MacBook Pro. The /.MobileBackups directory contains 19GB of data, but this data isn't being copied back to my Time Machine volume (network drive) when it is available. The reviews I've read also mention this syncing back to the Time Machine volume, but it doesn't appear to be working on my machine.

I've also noticed that local backups are being made when my Time Machine volume is available, sometimes even at the same time as when a "normal" Time Machine backup is being made. As far as I've understood, local backups should only be made when the the Time Machine volume isn't available.

Is anyone else seeing this behaviour?
Click to expand...

Yeah I've got the same issue and I dont know what to do. This is just using up space if it's not going to transfer to the time capsule when it is connected to it
 
I tried the terminal command and nothing happened. It prompted me to enter my password, which I did. When I hit enter nothing appeared to happen and the space on my hard drive hasn't increased.
 
For most people using Time Machine, I would recommend leaving this turned on. As others have stated, the intended behavior is to keep building snapshots of new or changed files while you're away from your TM drive, and transfer those changes over to the drive when you reconnect it. That way, you won't lose those snapshots in the interim.

How often it does garbage collection probably depends on the percentage of free space available. Taking up 19gb of mobile time machine storage on a Macbook Air with only 64gb available is a major problem, but a system with 500gb in it isn't so much. Perhaps it needs some tweaking, but I wouldn't worry about it.

That said, I've never used Time Machine and instead use Crashplan. Does a great job of doing backups to a centralized machine back at home, regardless if I'm local or remote over the internet. I have a family plan that lets me backup up to 10 computers for $12 per month unlimited, so it has offsite backups built in as well. It's awesome =).
 
This is a nasty little add-on from Apple. After cleaning up my verifications and doing disk repairs, my mac sped up nicely. But occ. it still got v. slow. Then I found a difference between Finder disk usage and the Disk Utility disk usage.

Checking :apple: -> About this mac -> more info -> Storage, i found that 105.2GB are being devoted to these local backups. Then noting that the slow-downs happen with activity of the tmutil, I promptly disabled it.

I hate when they make decisions on my behalf to try to "make life easier" for me. That's why OS X is still my second preference of OS (after Linux).
 
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