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Time Machine - Backup Runs out of space

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I'm using a 1gb usb drive to back up via time machine a 2012 MacBook Pro 13" with a 500gb ssd running Catalina 10.15.4

I've started getting the "Backup failed There isn't enough space on "BackupDrive" Message

I understood that Time Machine was supposed to manage deleting the oldest data by itself? I have seen advice on other sites to manually delete the oldest files on the backup disk, but also came across dire warnings from a respected member against doing that (https://www.mac-forums.com/forums/m...8-trash-time-machine-backups.html#post1849599)

But I've tried the advice there... re-formatting the backup drive and making another time machine copy... and for a while all is good - then the message comes back after a week or so. I've done this twice now with the same result

So starting over doesn't seem to give the happy ending it did on the other thread. And Time Machine doesn't seem to be handling the the old backups itself

I'd really appreciate any further suggestions, as it's annoying to have to do this every week or so! Should I risk manually deleting old files manually? That'd be quicker and less destructive of recent backups than starting over everytime... but I don't want to end up with a useless back up. Or is it time to give Time Machine the push?

Grateful for your thoughts
John
 

Slydude

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I'm using a 1gb usb drive to back up via time machine a 2012 MacBook Pro 13" with a 500gb ssd running Catalina 10.15.4
This is a good start. It's often recommended to have 1.5 to 2 tees more space on the backup drive than there is on the source drive so that's good.
I've started getting the "Backup failed There isn't enough space on "BackupDrive" Message

But I've tried the advice there... re-formatting the backup drive and making another time machine copy... and for a while all is good - then the message comes back after a week or so. I've done this twice now with the same result
That's a bit odd. I'm wondering if the backup drive got erased properly. Once you've erased the backup drive what does the Finder or Disk Utility tell you about how much space is available? How old is the backup drive?
 

IWT


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I agree. I suspect the EHD has seen better days. It shouldn't behave like this. Can't trust a Drive like that:sd Time for a new one, I reckon. Not expensive these days.

Ian
 
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I'm using a 1gb usb drive to back up via time machine a 2012 MacBook Pro 13" with a 500gb ssd
I'm assuming you mean a 1TB drive (not 1GB), right? And therefore by USB drive, I'm assuming you're talking about an external hard drive that connects via USB (not a USB stick/flash drive), correct? If I'm incorrect about either of those assumptions, that may be your issue (use a hard disk drive and be sure it's at least the same size if not larger than your main drive depending on how full you tend to keep your main drive and how far in time you want your backups to go).

Yes, Time Machine is supposed to automatically delete the oldest backup files for seamless backups. There's not even a UI option to disable this behavior, so unless you've somehow entered a Terminal command to change it, I would suspect the backup drive is the culprit, especially since you've already tried reformatting it. BUT...have you rebooted your Mac lately? If not, might be worth a shot to reformat the back drive again, reboot your Mac, and see if it works properly. If not, then buy a new HDD.
 
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Thanks for your thoughts folks, much appreciated

Of course 1tb not 1gb stupid me! And yes, it's an USB external HD - Toshiba Canvio Basics - 2.5 Inch (1TB) USB 3.0 Portable External Hard Drive - and I bought it March last year, so it's only just over a year old and has only been used for backups... but I guess it could have been faulty from start. As someone once said, "there are 2 types of hard drive - those that have failed and those that are about to fail!"

And when I re-formated it Disk Utility showed the usual near 1tb free each time, so I had no suspicions there. Can't imagine I'd have entered a terminal command by mistake - the last one i used was to unblock the Catalina update (I'd been holding off until I was sure there were no unexpected 32 bit programs lurking)

My 500gb drive is quite full... but I'm not worried about having backups going back too far - It's handy to be able to retrieve a file when I've "saved" instead of "saved as" - but I usually realise what I've done pretty quickly. In any case it's only saving a weeks worth of backups anyway. I really want an easy restore if the ssd goes down.

OK, the MBP has been rebooted several times, but I'll try reformatting again, rebooting, and try again one more time. if not, guess I'll try ordering another hard drive - as someone said, at £40 it's not a fortune, and you can never have too many backup drives!

What do you guys think about giving up on time machine... should I be thinking of another incremental backup system? I already use dropbox for docs and photos, so have a cloud based system for irreplaceable things, but I do like to have the equivalent of a disc image for quick restore, and TM is DESIGNED to work with Macs, isn't it?

Thanks for taking the trouble to reply everyone, much appreciated
John
 
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What do you guys think about giving up on time machine... should I be thinking of another incremental backup system? I already use dropbox for docs and photos, so have a cloud based system for irreplaceable things, but I do like to have the equivalent of a disc image for quick restore, and TM is DESIGNED to work with Macs, isn't it?
I've had zero issues with Time Machine and have never even considered for a second looking elsewhere for backup needs. It's quite seamless. I believe it's your external HDD that's the issue here, not Time Machine. I believe that once you replace the drive, everything will be smooth.
 
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I believe it's your external HDD that's the issue here, not Time Machine. I believe that once you replace the drive, everything will be smooth.
Thank you. I’m giving it one more try then back to Amazon! I don’t think I’ll get a Toshiba this time though!
 
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Thank you. I’m giving it one more try then back to Amazon! I don’t think I’ll get a Toshiba this time though!
After my last external HD failed, I opted to get a 2-bay SATA docking station and just use bare drives (SeaGate Barracuda). Not pretty, but works like a charm. Bonus is that it can clone drives if needed. I actually use one of those drives as extra storage for large files and the other as my Time Machine backup for both the other bare drive as well as my internal SSD on my iMac. I plan to upgrade to a 3-4 bay USB 3.0 dock when I get my new iMac and start doing redundant backups.
 
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When you reformat the drive, make sure it has a GUID partition scheme, it works better with macOS.


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The general rule of thumb is to have twice the space on the backup drive as the amount of data being backed up. So if your 500GB drive is, as you say, "quite full," then a 1TB backup drive should work. However, TM needs scratch space on the drive being backed up, so if you are "quite full" to the point of not leaving sufficient scratch space, backups will fail, no matter how much room is on the target drive. Even on SSD internal drives it's good to leave 5% or more free space for the system to use as scratch space.

Another factor is that the way TM works means that if you have a lot of really big files with high volatility (long videos being constantly revised, for example), then the thumbrule doesn't work so well. In that case you might need 4 or more times the space, depending on how far you want to go back.

Let me give some examples. Let's say your 500GB internal is at 490GB used. On first backup that 490GB is transferred to the backup drive as the base backup. Now an hour later any files that have changed are backed up, so let's say you were editing a 10GB file and have saved three histories in that hour, so that's 30GB, plus any other smaller files (Logs, plists, mail, texts, etc) that may have changed, so another 35-40GB is added to the backup. Now you continue editing that file for another 3 hours to get it right and each hour TM dutifully copies over 45GB to the backup. At the end of the day your backup will have 670GB used, approximately. Day two you decide to edit another video, this one 300GB. Your editor warns that you are out of space for history, but you press on, make the edit and let the history be lost. But the 300GB file has changed, so TM now copies that 300GB file, plus the other stuff, to the backup, so now you have about 975GB used on the backup drive in just two days. Pretty quickly you get to a situation where there is not sufficient space to make a new backup, but there are not enough backups on the drive for TM to do the juggling it needs to do to delete one of the backups in the middle, while preserving your history all the way back to the base backup for unchanged files and folders, so it throws up the error. How to fix it? Get a bigger drive, one sized to the way YOU work rather than the rule of thumb that works for most folks.

Think you don't use big files? Consider this: if you keep email going back years, that file and the database of attachments associated with it could well be gigabytes of storage, and every new message that comes in changes the file and the entire thing has to be backed up. Ditto for texts if you use Messages. Normally these are not large files, but they CAN get that way.

So what are you doing with your system that may make your backups larger than "normal?"
 

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Great example Jake.

Another file that can quickly get out of control in Time Machine backups are the files used for virtual machine programs such as union, Parallels, etc. So, say someone is running a virtual machine installation of Windows 10 and the initial installation used 60 GB of space for Windows. If you store that file in the standard location inside your Documents folder, every time you open tha file Time Machine considers it a "new" version of that file and has to back up the entire 60 GB.

×
 
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Good example, Sly! I used to have my virtual machines on the internal drive, but the backups every time I opened them were huge, so I moved the VMs to an external drive. Slightly slower boot, but I don't use them that often, so I put up with it.
 

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When I read about the way Time Machine handles VM files I was a little surprised. My understanding is that every time you open the file, TM thinks something has changed even if the contents of the tile hasn't changed. Because TM thinks the file has changed it creates a backup of that file.
 
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I think TM looks at the most recent time the file was written to for backups. When you open a VM, even if you don't do anything but boot it and then shut it down, the state of the file is changed, which then triggers TM. And since the VM is one file, all compressed together, TM can't just move what changed, it has to move the whole file. You can exclude the TM backup, of course, and use an internal backup system from within the VM to make separate backups of the VM that are outside the file, but that seems just too much work for me. I let TM do what TM is good at, but moved my VM images off the internal drive to an external that is periodically cloned to a backup as a precaution.
 

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At the time I think I excluded the VM files rather than move them to an external drive. I'm not running anything in a VM at the moment so it's not an issue.

If my understanding is correct that is exactly how Time Machine treats VM files.
 
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Thank you for such clear information on how Time Machine works - I've never been able to find that before.

I don't use/edit big files, I have photos, but they are not huge, and I don't do much editing. Most of my work involves word and excel files, and none are huge... but they are saved in a dropbox folder... I wonder if TM treats the whole DB folder like you are saying it treats VM - so even if I change or add a file of a few mb it then backs up the WHOLE of the DB folder? Just a thought.

Situation now is that I've re-formatted the backup disk and I now have full backup completed overnight

Stats are my SSD has 361GB used, 125GB free, the backup HDD has 689GB used - how on earth does that work then? But let's see how long it takes to use the remaining 320GB and whether TM manages itself. Probably won't know for about a week

Thanks so much everyone for taking the time to help me out - I'll let you know what happens

John
 

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Hi John

the backup HDD has 689GB used
That's not right (I don't mean you, I mean the 689GB).

Do you by any chance have any other EHD or Flash Drive attached when you are running a Time Machine Backup?

If you do, then TM will back those up as well unless you deliberately exclude them. The way to exclude them (if there are any) is: Open System Preferences > Time Machine > Options and you'll see a window with "Exclude these items from backups".

Then Drag those attached drives into that Window to stop them being backed up as well.

Most probably this does not apply to you, but it would be one plausible explanation.

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Thank you for such clear information on how Time Machine works - I've never been able to find that before.

I don't use/edit big files, I have photos, but they are not huge, and I don't do much editing. Most of my work involves word and excel files, and none are huge... but they are saved in a dropbox folder... I wonder if TM treats the whole DB folder like you are saying it treats VM - so even if I change or add a file of a few mb it then backs up the WHOLE of the DB folder? For which, after a few days, there may not be enough room Just a thought. But still doesn't explain why TM isn't deleting the older backups though...

Situation now is that I've re-formatted the backup disk and I now have full backup completed overnight

Stats are my SSD has 361GB used, 125GB free, the backup HDD has 689GB used - how on earth does that work then? But let's see how long it takes to use the remaining 320GB and whether TM manages itself. Probably won't know for about a week

Thanks so much everyone for taking the time to help me out - I'll let you know what happens

John
 
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Ah, sorry everyone, don't know how that got posted twice...

No, no other drives connected... it seems to have used twice the disk space of the original though.
 

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it seems to have used twice the disk space of the original though.
Yes, John. Which is absolutely crazy. I'm going to give this a great deal of thought and research as I'm sure the other contributors will do as well.

I can't help thinking that this is in some way related to the EHD. The partition set up or defective sections on the drive - I really don't know. But we won't give up;D

Ian
 
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