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What in the world is Time Machine backing up???

coolbreeze2

coolbreeze2

macrumors 68000
Original poster
Sep 24, 2009
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I don't understand what in the universe is Time Machine backing up! My MBA is only 256GB. The first backup was about 75GB which was very close to the size of the used space on the hard drive. I typed and saved a few documents and installed some very small apps. The backup size increased to 77GB. To me that was too big of an increase but I was oK with it. Then the backup size kept getting larger and larger although I was not installing anything and not saving anything. I was using the MBA only to surf the internet and watch streaming movies and streaming TV. I was not downloading anything!! Now the backup is 176GB and each back up says something like "backing up 50GB". Backing up what???? How is it that my available storage in About This Mac is 166GB of 245GB (245-166 =79) but my Time Machine backup is 176Gb? I could understand if I had downloaded some huge files and then later deleted them. Then maybe Time Machine is backing up what I deleted. However, as I said, I haven't downloaded nor saved anything!! I am tempted to dump Time Machine and try Carbon Copy Clone!!
 
Time Machine is not a clone backup. It's an incremental backup. Every single time something changes, Time Machine holds both the current and last version. And the version before that. And the version before that. And the version before that. Unless you've set a quota it'll continue to grow the size of the backup until there's no more space left, at which point it'll automatically clear the oldest. But Time Machine allows you to go back to any state any document has ever been in or your whole Mac for that matter.
 
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casperes1996 said:
Time Machine is not a clone backup. It's an incremental backup. Every single time something changes, Time Machine holds both the current and last version. And the version before that. And the version before that. And the version before that. Unless you've set a quota it'll continue to grow the size of the backup until there's no more space left, at which point it'll automatically clear the oldest. But Time Machine allows you to go back to any state any document has ever been in or your whole Mac for that matter.
Click to expand...
This is obviously very true!! It discourages me from using the trial version of various applications, especially the ones that are extremely large. If I decide to delete them, my Time Machine backup becomes bloated. I also noticed that I have some huge cache files. Currently 4GB. It would be great if I could exclude cache files from the backup but I tried and couldn't exclude them because I couldn't navigate to them when selecting an exclusion in Time Machine options. Is there a trick to excluding cache files?
 
MisterSavage said:
Time Machine lets you exclude things. I found that excluding ~/Library/Application Support helped.
Click to expand...
I do it differently; I excluded the System Library (I actually can't exclude System on Big Sur it seems - perhaps if I dig a little I might find out) and I would take Applications too because I would like to keep personal files that are in ~/Library/Application Support/

I can download all applications once again, but for restoring I'd like to have the files in here saved :)
 
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casperes1996 said:
Time Machine is not a clone backup. It's an incremental backup. Every single time something changes, Time Machine holds both the current and last version. And the version before that. And the version before that. And the version before that. Unless you've set a quota it'll continue to grow the size of the backup until there's no more space left, at which point it'll automatically clear the oldest. But Time Machine allows you to go back to any state any document has ever been in or your whole Mac for that matter.
Click to expand...

In reality it uses hard links to create copies of all files that haven't changed, and only creates copies of changed files. This however does mean that if you have a 20GB file and only change 1 byte, it's still going to have to backup all 20GB of that file again, thus leading to 40GB of backups for that 1 byte change.
 
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TiggrToo said:
In reality it uses hard links to create copies of all files that haven't changed, and only creates copies of changed files. This however does mean that if you have a 20GB file and only change 1 byte, it's still going to have to backup all 20GB of that file again, thus leading to 40GB of backups for that 1 byte change.
Click to expand...

That's the technical mechanism, yeah. When I was talking about incremental backups I didn't mean it as in incremental on a file storage level, but rather on a user experience level.
 
btw.. just as a thing to be aware of, recently I used Dupeguru to delete a bunch of duplicate files. I then without realizing that dupeguru creates a database file that will make Time Machine never finishing backing up.
I have a 1 TB drive for Time Machine and eventually the drive would fill up with only about 400 GB of data to backup. Time Machine eventually called it quits and reported that the drive was full.

the only reason I found out that Dupeguru causes this is because CarbonCopyCloner reported that there was an issue with this particular database file. The wording escapes me. I deleted Dupeguru's app support files and made a Time Machine backup once for just for kicks. Result = It's a OK.
 
TimeTracker is a great utility that will let you browse through your TM backups and see what's changed. If you find something big that's changing a lot, you can go into the settings as people suggest and exclude that. Pinpointing what it is will help you target the exclusion more precisely.

TimeTracker​

TimeTracker is a quick-and-dirty application that displays the contents of your Time Machine backups, and shows what's changed since the previous backup. TimeTracker is in an extremely early state, and is as such very unpolished.

  • Download TimeTracker (prerelease), which works with 64-bit Intel Macs running OS X 10.10.x (Yosemite) or greater.
Click to expand...

Don't mind the "extremely early state" stuff -- I've been using this for easily 10 years if not more and it's always been "prerelease" LOL. It works fine, but give it a while on first launch to scan through stuff.
 
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coolbreeze2 said:
I don't understand what in the universe is Time Machine backing up! My MBA is only 256GB. The first backup was about 75GB which was very close to the size of the used space on the hard drive. I typed and saved a few documents and installed some very small apps. The backup size increased to 77GB. To me that was too big of an increase but I was oK with it. Then the backup size kept getting larger and larger although I was not installing anything and not saving anything. I was using the MBA only to surf the internet and watch streaming movies and streaming TV. I was not downloading anything!! Now the backup is 176GB and each back up says something like "backing up 50GB". Backing up what???? How is it that my available storage in About This Mac is 166GB of 245GB (245-166 =79) but my Time Machine backup is 176Gb? I could understand if I had downloaded some huge files and then later deleted them. Then maybe Time Machine is backing up what I deleted. However, as I said, I haven't downloaded nor saved anything!! I am tempted to dump Time Machine and try Carbon Copy Clone!!
Click to expand...
Does sound a little strange.
 
HDFan said:
Not a great idea. A lot of applications keep important data there - 1Password, Adobe apps, App Store, Evernote, iStat, Microsoft, Parallels, Plex, Steam, VLC, XCode, and hundreds more. If you need to do a complete restore ....
Click to expand...
I actually have done a full restore when the Apple Store wiped my Mac and didn't encounter any issues when I restore from TM. Still it might not be a bad idea for me just to limit the worst offenders.

My 1Password seems to be backing up here and not ~/Library/Application Support.

~/Library/Group Containers/YYY.com.agilebits/Library/Application Support/1Password/backups
 
Experiences like this are why I gave up on Time Machine altogether about a year ago, after several failed or hung backup attempts that went no where for days. I was a happy Time Machine user since its debut with Mac OS X Leaopard in 2007. It worked particularly well when running on a networked Apple Time Capsule router+NAS. It was like magic, and it stayed that way for over a decade.

Then, something changed. It may've been the transition to APFS, or FileVault, or who knows what else, but Time Machine simply stopped working for me in the trusty reliable way it had since 2007. I even stopped doing networked Time Machine backups, and went for just simple USB hookups. Nothing got past backups that would never finish, or get corrupted after a few weeks.

I grew so frustrated, I sought out other solutions, and finally settled on Carbon Copy Cloner, by indie developer Bombich Software. I couldn't be happier. It's not as native and "magical" as Time Machine, but it's most of the way there. For anyone frustrated by Time Machine the last couple years, give CCC or its competitor SuperDuper a try.
 
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dukee101 said:
Experiences like this are why I gave up on Time Machine altogether about a year ago, after several failed or hung backup attempts that went no where for days. I was a happy Time Machine user since its debut with Mac OS X Leaopard in 2007. It worked particularly well when running on a networked Apple Time Capsule router+NAS. It was like magic, and it stayed that way for over a decade.

Then, something changed. It may've been the transition to APFS, or FileVault, or who knows what else, but Time Machine simply stopped working for me in the trusty reliable way it had since 2007. I even stopped doing networked Time Machine backups, and went for just simple USB hookups. Nothing got past backups that would never finish, or get corrupted after a few weeks.

I grew so frustrated, I sought out other solutions, and finally settled on Carbon Copy Cloner, by indie developer Bombich Software. I couldn't be happier. It's not as native and "magical" as Time Machine, but it's most of the way there. For anyone frustrated by Time Machine the last couple years, give CCC or its competitor SuperDuper a try.
Click to expand...
CCC and Arq are the two best, in my opinion.
 
Apple_Robert said:
CCC and Arq are the two best, in my opinion.
Click to expand...
Yes, agreed. Also: it didn't help that one of the grandmasters of the Time Machine community, James "Pondini" Pond passed away some years back, taking with him an invaluable third-party resource on how to use and troubleshoot Time Machine. Pondini had put together a true "missing manual" for the product, better than Apple ever did. Obscure Terminal commands to diagnose issues, you name it.. he had it all documented. You'll be missed Pondini 😢
 
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dukee101 said:
Yes, agreed. Also: it didn't help that one of the grandmasters of the Time Machine community, James "Pondini" Pond passed away some years back, taking with him an invaluable third-party resource on how to use and troubleshoot Time Machine. Pondini had put together a true "missing manual" for the product, better than Apple ever did. Obscure Terminal commands to diagnose issues, you name it.. he had it all documented. You'll be missed Pondini 😢
Click to expand...
Do you have a link for this missing Time Machine manual? Thanks in advance.
 
MisterSavage said:
I actually have done a full restore when the Apple Store wiped my Mac and didn't encounter any issues when I restore from TM. Still it might not be a bad idea for me just to limit the worst offenders.

My 1Password seems to be backing up here and not ~/Library/Application Support.
Click to expand...

A full restore from TM via migration assistant will restore the Application Support directory. Dunno where all of those apps keep their data, but 1Password seems to keep all of its backups there.
 
ignatius345 said:
TimeTracker is a great utility that will let you browse through your TM backups and see what's changed. If you find something big that's changing a lot, you can go into the settings as people suggest and exclude that. Pinpointing what it is will help you target the exclusion more precisely.



Don't mind the "extremely early state" stuff -- I've been using this for easily 10 years if not more and it's always been "prerelease" LOL. It works fine, but give it a while on first launch to scan through stuff.
Click to expand...
Ok I am trying it now and it's doing the initial scan.
 
dukee101 said:
Experiences like this are why I gave up on Time Machine altogether about a year ago, after several failed or hung backup attempts that went no where for days. I was a happy Time Machine user since its debut with Mac OS X Leaopard in 2007. It worked particularly well when running on a networked Apple Time Capsule router+NAS. It was like magic, and it stayed that way for over a decade.

Then, something changed. It may've been the transition to APFS, or FileVault, or who knows what else, but Time Machine simply stopped working for me in the trusty reliable way it had since 2007. I even stopped doing networked Time Machine backups, and went for just simple USB hookups. Nothing got past backups that would never finish, or get corrupted after a few weeks.

I grew so frustrated, I sought out other solutions, and finally settled on Carbon Copy Cloner, by indie developer Bombich Software. I couldn't be happier. It's not as native and "magical" as Time Machine, but it's most of the way there. For anyone frustrated by Time Machine the last couple years, give CCC or its competitor SuperDuper a try.
Click to expand...
I wanted to try CCC but its website said that a network NAS backup is not recommended. I invested in an expensive 6TB NAS a last year or earlier (I don't remember when) to use for my Time Machine backups for my Macs. If I use CCC the money I spent on the NAS will be waisted. Is CCC not usable with a NAS?
 
coolbreeze2 said:
I wanted to try CCC but its website said that a network NAS backup is not recommended. I invested in an expensive 6TB NAS a last year or earlier (I don't remember when) to use for my Time Machine backups for my Macs. If I use CCC the money I spent on the NAS will be waisted. Is CCC not usable with a NAS?
Click to expand...
CCC can backup to a disk image. Make a disk image on the NAS, mount it on your Mac, and do the backup. When done, Eject the disk image like any other disk.
bombich.com

Backing up to a disk image - Bombich Software

bombich.com bombich.com

CCC can create disk images for you, but it guesses at what the max size will be (as explained at above link). If it guesses too small, you'll run out of space on the image, even with plenty of space on the NAS. I recommend making a disk image of the sparsebundle type using Disk Utility, and make it the size you want, rather than letting CCC guess.

Create a disk image using Disk Utility on Mac

Use Disk Utility on your Mac to create a disk image.
support.apple.com

A disk image isn't bootable, but neither would a backup residing on a NAS be botable, so nothing's lost by using a disk image in this situation. If it were a disk image on an external disk, then the loss of bootability vs. cloning directly to the disk might be important to you.

You can even make multiple disk images on the NAS, one for each Mac, or some other organizing principle, such as "Ancient Files" vs. "Modern Files" or arranged by decade (2010-2019, 2020-2029. etc.)
 
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coolbreeze2 said:
I wanted to try CCC but its website said that a network NAS backup is not recommended. I invested in an expensive 6TB NAS a last year or earlier (I don't remember when) to use for my Time Machine backups for my Macs. If I use CCC the money I spent on the NAS will be waisted. Is CCC not usable with a NAS?
Click to expand...
If it was me, I'd consider a CCC clone in addition to your networked Time Machine backup. If you're just backing up a 256GB MacBook Air drive, you could get by with a really basic USB drive.

CCC is awesome, but TM has a really good interface for recovering versions of files and is dead simple to set it and forget it (when it's working right). I say use both, once you get your oversized backup situation sorted.

My strategy is to do a CCC backup of everything I own (externals and everything) onto a big 4TB portable drive, which I then keep offsite away from the house. I do that every month. Then day to day backup is just handled by Time Machine. That's more for "I effed up this file by mistake" type stuff. The CCC backup is more for a disaster recovery scenario. That said, I've migrated to new Macs on several occasions just using a Time Machine backup and it's worked very well.

Not for nothing but I gather from here the Big Sur version of Time Machine is quite a bit better than earlier versions.
 
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dukee101 said:
Yes, agreed. Also: it didn't help that one of the grandmasters of the Time Machine community, James "Pondini" Pond passed away some years back, taking with him an invaluable third-party resource on how to use and troubleshoot Time Machine. Pondini had put together a true "missing manual" for the product, better than Apple ever did. Obscure Terminal commands to diagnose issues, you name it.. he had it all documented. You'll be missed Pondini 😢
Click to expand...
Howard Oakley seems to have a lot of in-depth info on Time Machine (among other things). A lot of it is over my head, I'm afraid, but it's here: https://eclecticlight.co/?s=time+machine
 
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