Not Enough Space to Copy 2 TB to an Empty 6 TB Drive.

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Level 1

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Not Enough Space to Copy 2 TB to an Empty 6 TB Drive.

My 2 TB Time Machine drive filled up and started deleting my older backups (without warning!), so I bought a brand new 6 TB drive to replace it. I started copying the contents of my old drive to my new one on Thursday afternoon. It took about 33 hours for it to finish PREPARING to copy 9,296,358 files (at which point it stopped and waited for my password). It finally finished some time Sunday night/Monday morning. Except it didn't finish. There wasn't enough free space on the empty 6 TB drive to copy 2 TB to it. It's copied a LOT of files, but there's no way for me to tell which files copied and which didn't. But more importantly, how can there only be 12 MB free on this new 6 TB drive??? Even if I figured out the missing files, there's no space for them!

Am I doing something wrong? Should I have tried copying a folder at a time, instead of all at once? Is there a better way to move to a new TM drive? Do I have to reformat the new drive and start this 4-day-long process over again?

iMac Line (2012 and Later)

Posted on Sep 20, 2021 7:46 AM

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Answer 1

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VikingOSX

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116,813 points

Sep 20, 2021 10:11 AM in response to John Baro1

A Time Machine drive should be formatted as GUID HFS+ case-insensitive (the default) Journaled. The operating system is installed as case-insensitive, and third-party applications expect this too.

If that 6TB drive is full and contributed to by a running Time Machine (current data), then I would recommend that you check what is on it, and if sacrificial content, reformat it as in the first sentence.

No guarantees that Disk Utility will not run into a temporary storage issue during that copy process. I believe Disk Utility will preserve permissions and Access Control Language (ACL) settings on the data, whereas a Finder drag and drop copy operation may not. I don't deal with n-tuple TB TM data, so have no first-hand experience merging old TM drive content onto a newer, larger device. On a new operating system installation, I always start with a new TM drive that is at least 3x the capacity of the startup drive, and do not reuse the previous TM devices, other than an initial migration of user data onto the new operating system.

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Answer 2

Sep 20, 2021 8:29 AM in response to John Baro1

That wasn't a spare 2TB on your boot drive for temporary storage during the copy process. You might try this 2TB to 6TB via Disk Utility Restore feature. You may again, run up against temporary storage constraints, but worth a try.

Recommend that you turn off Time Machine during the Disk Utility process of 2TB -> 6TB.

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Answer 3

John Baro1 Author

Level 1

74 points

Sep 20, 2021 8:59 AM in response to VikingOSX

Both the old and new drives are formatted the same, macOS Extended, Case-sensitive, Journaled. It won't start the copy if they don't match (as I discovered). I did turn off TM during the copy. It's still off.

If it's a temporary storage issue, I don't want to start another multi-day process over again just to see it fail. Seems like copying smaller chunks of data at a time might be a better solution.

I get why the copy might fail, but I still don't understand how my 6TB is completely full. What's taking up all that space on the new drive?

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Answer 4

John Baro1 Author

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74 points

Sep 22, 2021 12:36 PM in response to VikingOSX

This is not just a temporary storage issue. I've watched the copy process and notice that it starts normally, counting down the number of files to copy, and counting up the GB copied. But when it reaches zero files left to copy, it keeps going. The GB copied keeps going up, the files remaining stays at zero, and the time remaining stays at 5 seconds. It continues until the drive is filled. I've tried this a few times now, with the entire backups folder and with one sub-folder at a time. Only one sub-folder copied successfully, all the others kept counting up to infinity.

It looks like there's also something going on with the way TM formats data. The first 3 folders I tried to copy were each 600-700 GB. That's on a 2 TB drive. How can all of those over 100 folders each have 100s of GB in them?

I also tried to do a Restore in Disk Utility, which is a recommended method for copying TM disks. It would not copy, says the device is not valid for restoring. After doing a little research, it looks like most, if not all, disk copying utilities will NOT work with TM volumes.

I've been at this for a week now, no closer to moving to a larger TM drive than I was when I started. Is there no way to copy a large Time Machine volume?

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Answer 5

Sep 22, 2021 1:56 PM in response to John Baro1

And macOS is installed as case-insensitive… and all of my TM drives over the years have been formatted case-insensitive too.

As I have had no reason to migrate an older TM drive to a larger one over the years, I doubt if I can be of any more help in this post.

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Answer 6

BDAqua

Level 10

245,483 points

Sep 22, 2021 2:21 PM in response to John Baro1

I think it's likely using/counting all the Aliases in theTM backup as real data, where TM just "points" to older unchanged data in every backup.

If unable to use another Mac to copy it or that doesn't work, then I'd use this drive as a standby & get a new drive & format it as case-insensitive.

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Answer 7

John Baro1 Author

Level 1

74 points

Sep 22, 2021 6:37 PM in response to BDAqua

I tried a couple of other backup programs I have. AASync could not read the TM volume, but ChronoSync can (with admin access). It's running now, but provides no estimate of time. Though at 12-14 MB per sec, it's going to be another long time to wait before I find out if all 2 TB copied successfully.

My last resort is to just start a new TM backup on the new drive. I hate to lose my old backups, but since TM started dumping files when its drive filled up, it looks like my TM backup only goes back about 24 hours.

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Answer 8

John Baro1 Author

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74 points

Sep 23, 2021 5:08 PM in response to BDAqua

I recently learned that when the TM volume gets close to full, it starts dumping files. The TM control panel says it goes back to 2/2020, but all the files I've been working on recently only go back 24 hours. Programming involves LOTS of files being changed frequently, so I guess that really eats up space with hourly backups. And TM deletes files as necessary without any warning.

ChronoSync has now been running for a little over 23 hours, and it's copied 2 TB of the 1.95 TB on the original drive. Yes, it's copied more than there is to copy, assuming the Finder really knows what's on the TM volume. I'm starting to worry that it will just keep counting up to infinity like when I tried using the Finder to copy.

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Answer 9

John Baro1 Author

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74 points

Sep 24, 2021 3:27 PM in response to BDAqua

ChronoSync also failed. After 30+ hours, just like the Finder, it had copied well over 2 TB (4 of 133 folders) when the source volume contained only 1.95 TB. ChronoSync tech support explained why this happens:

ChronoSync won't work to copy the contents of Time Machine backups. The reason is that Apple had to bend the UNIX rules by allowing hard links to directories in order to pull this off. Hard links to directories have been avoided in the UNIX world because of the potential for some infinitely recursive directory references that would be undetectable by program logic (or at least extremely hard to detect). Apple decided it was okay to do this in a controlled environment, namely Time Machine backups.

From what I've found on the inter webs, no other Mac backup software will copy a TM volume. So, you can't copy a TM volume using the Finder, as Apple's support doc recommends, nor using Disk Utility, nor any other 3rd party utility. It's starting to look like it is IMPOSSIBLE to copy a Time Machine volume.

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Answer 10

steve626

Level 6

11,501 points

Sep 25, 2021 10:42 AM in response to John Baro1

John Baro1 wrote:

My last resort is to just start a new TM backup on the new drive. I hate to lose my old backups, but since TM started dumping files when its drive filled up, it looks like my TM backup only goes back about 24 hours.

I have copied these Time Machine volumes successfully in the past, as you are trying to do. But I have never had them as case-sensitive, not sure if that would explain your issues. I would think it would work either way.

If you start a new TM backup on the blank new drive you won't lose your old backups on the old 2 TB drive. You can keep it as "archive" for older backups (but if it only goes back 24 hrs that's not much of an archive) and can still access those older backups as necessary from the old drive, while not adding to it going forward (as it is full).

Do you have large virtual machine files that you are backing up? I am wondering why your backups only go back 24 hours, large virtual machine files, unless excluded from Time Machine, often get re-backed up every time because small changes (or just having the virtual machine running) makes the file look "changed" and hence another ~ 50 GB gets backed up. So the Time Machine drive can fill up fast and hence the loss of the older backups as it makes room for new ones.

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Answer 11

BDAqua

Level 10

245,483 points

Sep 20, 2021 8:12 AM in response to John Baro1

What Format is the new 6 TB drive?

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Answer 12

John Baro1 Author

Level 1

74 points

Sep 22, 2021 12:38 PM in response to VikingOSX

I don't know why my TM drive is formatted as case-sensitive. It's always been that way, and always worked. The Finder will only let me copy it to a drive with the same formatting.

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