Carbon Copy Cloner 7 - Users Thread

[dai-leung]

I've used three different ways of creating the bootable backup disk:
1. Using the 'Legacy bootable installer' function in CCC.
2. Using the regular macOS installer to create a new macOS installation on the volume, then selecting 'Macintosh - Data' as the destination for the CCC backup task.
3. Using the regular macOS installer to create a new macOS installation on a volume already containing CCC backup(s)/snapshots of the 'Macintosh - Data' volume. It's smart enough to create the volume group and keep the existing Data volume.

CCC7, external boot, OLPC

For me, CCC is a cannot-do-without backup software, far more useful to me than Time Machine. It saved my mac from disaster numerous times. Also CCC's support is so helpful, sometimes Mr. Bombich answered my often elementary questions. I was more than glad to pay for the upgrade to CCC7.

I have a mac with OCLP. There were several times that my screen was corrupted, making it nearly impossible to click on CCC to restore my mac. Not a computer person, in the past I often worried that my mac would break and I had no way to restore it. By chance, I came across a youtube video tutorial by Mr. Macintosh showing how to install macOS and OLPC on an external drive (

). I followed the steps and was able to install OS 14.7 and OLPC 1.5.0 on an external SSD. I was also able to use migration assistant to migrate contents from mac to the SSD with a CCC backup as a source.

However, unlike in Ben J’s post, on CCC7 “Macintosh-Data” of the external boot drive was not visible, only the whole volume group was visible. When I used CCC7 to backup to the volume group of the external boot drive, it became non-bootable and thus became useless.

I created a volume on the external boot drive and used it as a second external CCC backup by scheduling a timing offset from the another CCC backup on a different external drive. Unlike Time Machine, CCC makes all the drives available as a source or destination. This feature allows me to use a CCC backup or a snapshot on either external drive to restore my mac. This avoids a single point of failure. Also the mac OS installer allows me to reinstall the OS and OLPC on the internal drive quickly. All these points were pointed out by Ben J in his post.

 

[dai-leung]

CCC6, CCC7, delete Time Machine snapshots

With low technical skill, for me, it is much easier to use CCC to delete a Time Machine snapshot than using the terminal.


CCC does not allow CCC6 and CCC7 to be used on the same Mac at the same time. In CCC7, on the TM backup volume, the “snapshot” button is disabled and as a result, I could no longer delete TM snapshot. However, CCC6 still allows enable the “snapshot button”. So I installed macOS on an external drive and use CCC6 there to delete TM snapshots as CCC allows access to all the mounted external drives. This is a hard way to delete a TM snapshot.

 

[dai-leung]

Migration Assistant, restore from a CCC7 and Time Machine backup

I have some questions about CCC backup and snapshots. Hope someone could help to if my understanding is correct and if I had done something wrong.

First I wish to check if my understanding is correct which is during the first backup, CCC copied the entire Macintosh HD data volume to the external disk. After that it does a differential backup. After each backup, it creates a snapshot. At any given time, the external disk is a mirror image of the MHD data volume. On day X, there is only one backup which is the latest and many snapshots. Is this correct ?

I checked all the CCC snapshots, they have all the files needed to restore the Mac. So they are equivalent to backups. Is this correct ?

I ran into the following problem while using CCC7 to restore:

My Mac was not working properly and I wanted to re-install the OS using a macOS installer installed on an USB drive. Misguided, just before the installation, I did a CCC backup, which I later realized I was creating a backup of the Mac that was not working properly and in the process deleted the previous good CCC backup.

Nonetheless, I went ahead to re-installed macOS to my Mac. As instructed by CCC, when one is migrating contents to a new Mac, Migration Assistant must be used. I then use Migration Assistant to port over contents from CCC (as source) to the Mac. To my dismay, in MA CCC did not offer me a selection of all its backups. I had only one choice which was the CCC backup of the malfunctioned Mac. So I stopped and restored from the snapshot which was made before the Mac malfunctioned. However, after I did that, the Mac became non-bootable.

I then re-installed macOS and repeated the above restore procedure, but this time in Migration Assistant, I used Time Machine as a source. TM allowed me to select from one of its many backups. So I selected one before the Mac malfunctioned and the Mac was successfully restored with the exception that I created a new user on my Mac that I don’t want.

Did I do "restore" wrong?

 

[gilby101]

First I wish to check if my understanding is correct which is during the first backup, CCC copied the entire Macintosh HD data volume to the external disk. After that it does a differential backup. After each backup, it creates a snapshot. At any given time, the external disk is a mirror image of the MHD data volume. On day X, there is only one backup which is the latest and many snapshots. Is this correct ?

Not quite. "Differential" is not a good word to use, it has overtones of tape backup where a first complete backup is made followed by many backups each of which has all the changes since that first backup. This is not what TM and CCC do. "Incremental" is a better term as each backup only copies files (often only parts of files) and metadata which have changed since the previous backup.

But, with CCC/TM the storage of the backups (first and incrementals) is much more sophisticated than a tape drive. Using APFS as the store allows each backup to be presented as complete in itself - as a snapshot. The snapshots all have equal standing as far as APFS is concerned. Consequently any backup snapshot (including the first and last) can be deleted.

All snapshots can be mounted as a volume. Finder shows all TM snapshots because they are all mounted as file systems. But for CCC snapshots Finder only shows the latest snapshot. Just the latest is mounted automatically, the others are mounted when requested via the CCC app. They then become visible in Finder.

With low technical skill, for me, it is much easier to use CCC to delete a Time Machine snapshot than using the terminal.

And easier still to use Disk Utility. It has menu item View > Shows APFS Snapshots. A bit slow to find them on a HDD. In this way DU shows all TM and CCC snapshots. I doubt it would worry whether the snapshots were CCC6 or CCC7. You can delete as you want.

Did I do "restore" wrong?

You got your data back, you were successful! But it could have been better.

1. You should (if possible) do the Migration Assistant before creating any users - i.e. as part of the install. That is the only way to do a precise restoration.

2. Migration Assistant should have presented all snapshots for you to choose from.

3. Only seeing the latest CCC snapshot suggests something wrong with your CCC backup configuration. Maybe someone else will be clearer on that.

 

[dai-leung]

As always, I appreciate your knowledgeable and educational reply !

And easier still to use Disk Utility. It has menu item View > Shows APFS Snapshots.

My Mac has Sonoma 14,7 and it does not show APFS in DU. Will downgrade to 14.6.1 to see if it shows.

You should (if possible) do the Migration Assistant before creating any users

I may have made an mistake and will try again to see if I could achieve the desired result.

2. Migration Assistant should have presented all snapshots for you to choose from.

3. Only seeing the latest CCC snapshot suggests something wrong with your CCC backup configuration. Maybe someone else will be clearer on that.

I would appreciate if someone could help by going into Migration Assistant (application/utilities/Migration Assistant) and chose CCC as the source to see if CCC presents the option of many backups or just one backup, then stop without completing the migration process.

 

[dai-leung]

would appreciate if someone could help by going into Migration Assistant (application/utilities/Migration Assistant) and chose CCC as the source to see if CCC presents the option of many backups or just one backup,

Please ignore the above. Mr. Bombich replied that in MA, ccc only offers only one choice, the latest backup. Apple won’t let CCC offer all backups that it has.

Then he said something I don’t understand. If I want to use a specific snapshot, I have to use on a “new volume”. Just over my head.

 

[Ben J.]

Please ignore the above. Mr. Bombich replied that in MA, ccc only offers only one choice, the latest backup. Apple won’t let CCC offer all backups that it has.

That's a limitation in Migration Assistant. It's designed to import an extisting user account.

Then he said something I don’t understand. If I want to use a specific snapshot, I have to use on a “new volume”. Just over my head.

He means; if instead of MA, you use an app like CCC or Disk Utilities, you'll be able to choose between all available snapshots to clone from, not import from - and the clone will have to be done to a fresh, empty volume (APFS).

In other words, there are mainly two ways to restore an existing user account to a new disk or mac;
• Install macOS. On first boot, use Migration Assistant to import the user from a drive or connected mac.
• Install macOS. Boot from a secondary bootdrive, run CCC, DU or similar and clone the "Macintosh HD - Data" volume from the old drive to the new internal drive. (Edit: This will of course recreate all the user accounts that migh exist on the volume. You'll have the option to restore from any available snapshot.)

 

[dai-leung]

• Install macOS. Boot from a secondary bootdrive, run CCC, DU or similar and clone the "Macintosh HD - Data" volume from the old drive to the new internal drive.

My Problem: how to use a specific CCC snapshot (instead of the CCC backup) as a source in Migration Assistant

I read many of your posts. You are knowledgeable and experienced in Mac. I am grateful to have your response. This problem is really beyond my skill thus welcome your help.

The problem I had was that the Mac was corrupted or not function correctly. Thus cloning the MHD - Data may be cloning a bad volume.

Mr. Bombich further said: “Rather you would restore the snapshot to the (empty) external drive, then you could use that external drive as a source to Migration Assistant.”—- This I can understand.

 

[Ben J.]

My Problem: how to use a specific CCC snapshot (instead of the CCC backup) as a source in Migration Assistant

MA can't read snapshots.

Mr. Bombich further said: “Rather you would restore the snapshot to the (empty) external drive, then you could use that external drive as a source to Migration Assistant.”—- This I can understand.

That would be a nice workaround to let MA import from a snapshot.

The problem I had was that the Mac was corrupted or not function correctly. Thus cloning the MHD - Data may be cloning a bad volume.

If you have an external drive, this is what I'd try:
• Use Disk Utilities to create a new volume on the external, and use the "Restore" function (basically means clone) to clone from a snapshot that you think is the one you want - clone it to the new empty volume you created on the external.
• Use the new clone of the snapshot for user account import in MA.
But I must admit, I don't really have a sense of understanding completely your situation.

 

[Realityck]

My Problem: how to use a specific CCC snapshot (instead of the CCC backup) as a source in Migration Assistant

I read many of your posts. You are knowledgeable and experienced in Mac. I am grateful to have your response. This problem is really beyond my skill thus welcome your help.

The problem I had was that the Mac was corrupted or not function correctly. Thus cloning the MHD - Data may be cloning a bad volume.

Mr. Bombich further said: “Rather you would restore the snapshot to the (empty) external drive, then you could use that external drive as a source to Migration Assistant.”—- This I can understand.

Anytime you do a CCC standard backup or legacy snapshot APFS copy to a external volume of a usable MacOS installation it provide everything necessary for wipe and reinstall MacOS then use Migration Assistant after you boot from the fresh MacOS installation to import all your system settings, Applications, data for a full restore. The external volume is known as a ASR volume.

Transfer to a new Mac with Migration Assistant - Apple Support

Use Migration Assistant to copy your files from another computer.

support.apple.com

Most of the time when you have something weirdly off with a MacOS you do a DFU restore. DFU stands for Device Firmware Update which reloads the software and the firmware of your device to factory settings. This is a "complete wipe"of boot volume and redo of the Macs FW. Having everything on a external volume that is usable as a ASR (Apple Software Revery) volume means you can take it to a store for them to do a DFU restore and then they use your ASR volume for complete restore back to the last snapshot or standard backup.

 

[dai-leung]

try:
• Use Disk Utilities to create a new volume on the external, and use the "Restore" function (basically means clone) to clone from a snapshot that you think is the one you want - clone it to the new empty volume you created on the external.
• Use the new clone of the snapshot for user account import in MA.

Anytime you do a CCC standard backup or legacy snapshot APFS copy to a external volume of a usable MacOS installation it provide everything necessary for wipe and reinstall MacOS then use Migration Assistant after you boot from the fresh MacOS installation to import all your system settings, Applications, data for a full restore. The external volume is known as a ASR volume.

Sincere thanks to you both!

The method does work and I sincerely appreciate your help! I re-installed macOS, used CCC to "restore" the desired snapshot to a volume as you both had suggested, then used the volume as a source in Migration Assistant. The mac reboot correctly with all the files I had in the snapshot and all the apps also worked correctly without the need to re-register. Compare to Time Machine, cloning the snapshot is an extra step. But the important thing now I could use a CCC snapshot to restore my mac which I erroneously and previously thought was not possible.

You both are very kind to help me out.

DFU stands for Device Firmware Update which reloads the software and the firmware of your device to factory settings. This is a "complete wipe"of boot volume and redo of the Macs FW.

This is way above my skill but thanks just the same!

 

[Ben J.]

That's great to hear!
Thanks for reporting back.

 

[dai-leung]

Adding a second Time Machine drive: APFS or journaled

Some members in this thread also do TM backup and may find my observation interesting. I wanted to add a second TM drive to my TM backup, had encounter great difficulty and spent days in doing it without success because the drive I wanted to add just won't show up on the TM add-disk selection list . I thought my macOS was too new. Frustrated and went as far as installing an older version OS just to add another disk but I failed too. Then I observed that for an APFS formatted disk, only the first volume (sometimes also the second volume) of the first container shows up on the add-disk selection list; the rest containers (and partitions) and their volumes just don't not show up. This explains why I couldn't add my desired volume or partition to the list of TM backup.

I have an old WD drive. When connected to the mac, all its partitions showed up on the add-list! I checked, they are all journaled formatted. Thus the key is the "journaled format". So I went back to the SSD and created a journaled formatted partition and vola, it showed up on the add-disk list! Knowing when do a TM backup, TM will re-format the disk to APSF. I did a TM backup on the journaled formatted disk, sure enough it got converted to APSF and the TM backup was successful and as intended. TM backs up to the two drives alternately at 2 hours interval and 1 hour offset from each other.

Another interesting aspect is that volumes in the first container are listed alphabetically. I can change the name of the last volume (which does not appear in add-disk list) for example XXX to A-XXX, which then float to the top of the container and thus will appear in the add-disk list.

 

[dai-leung]

CCC7: If someone could help explain what the following mean and if I should select them when backup, I would greatly appreciated it.

1) Protect root-level items on the destination

2) Troubleshooting Settings
--- I don't have the skill to troubleshoot, so I just leave them all un-selected, yes? Likewise for "Postflight", yes?

3) Performance & Analysis
What is "record of transactions"? How do I use it?
"Find and replace corrupted files", should I turn it on? Will it slow down the backup?

4) What is "File copier CPU priority"? why default to the highest level?
What is "File copier CPU concurrency"? why default to the lowest level?

 

[dai-leung]

I wrote previously CCC did not allow CCC6 and CCC7 license to be used at the same time. I was wrong. My apology.

I download and installed both CCC6 and CCC7 on the mac provided the respective license key for each.

I can now run either version. But after running CCC7 then run CCC6, the following screen will show up. Just select "Downgrade", then CCC6 will run. In CCC6 the "Snapshots" on the Time Machine table can be enabled allowing snapshot to be deleted. In CCC7, that button is grayed out.

 

[dai-leung]

I want to do the following experiment to gain better understanding about the relationship between CCC snapshots and Time Machine snapshots, but a bit worry it may ruin my mac so want to check with the experts on this forum first.

The situation is: for the last 12 months, I have been doing CCC and Time Machine backups monthly. On month 12, I restore the Mac using the TM snapshot of month 0 (that is when the new Mac was just bought and was used for the first time, no app had been installed yet), the virgin state.

After that can I use the CCC snapshot of month 12 to restore the Mac to its state on Month 12? Hope I could get some advice; your advice will be appreciated.

 

[Realityck]

CCC 7.0.3-b1 (8055) is now available — This is a pre-release update of CCC 7.0.2 (8048)

Spoiler: CCC 7.0.3-b1 Fixes and Changes

• Fixed
  Fixed an issue in which CCC's helper was occasionally not completely exiting on startup in cases where there were no scheduled tasks. This was leading to cases where the task history database would be closed, thus disallowing new entries to be recorded.
• Changed
  Improved the experience of editing a password in the email server settings panel.
• Fixed
  Addressed an edge case scenario where file ownership/permissions were preserved despite using the "Don't preserve permissions" advanced setting in cases where files were cloned via the APFS clonefile() method (i.e. in cases where the source and destination are folders on the same APFS volume).
• Changed
  CCC will apply a more strict 5GB minimum free space requirement when the destination is the startup disk (or a volume in the same APFS container as the startup disk).

 

[dai-leung]

Please help setting up CCC retention.

I have a 2TB SSD for CCC and Time Machine backups -- one partition with 2 volumes. So CCC and TM each has about 1TB. Each snapshot seems to consume about 0.5GB (just guessing, based on the released GB on CCC snapshot table).

"get information" shows my Macintosh HD consumed ~100GB. CCC does its first backup which will consume ~100GB. I am left with ~900GB for use by snapshots

For the numbers given below, after sometimes, I will have 720+90=810 hourly and daily snapshots, consumed 405GB. I am left with ~500G or 1,000 snapshots for the "every 3 days" snapshots, which will take ~10 years till disk is full.

Is my calculation correct?

 

[dai-leung]

I remember reading on this forum that the correct way of calculating how much storage a snapshot consumed is to use the CCC “Snapshot” memory consumption on the "Volumes” page. Obviously, the average is obtained by dividing the total memory consumption by the number of snapshots given on the snapshot table. I thus revise my post as follows.

Please help setting up CCC retention.

Using CCC “Volumes” and storage consumed by “Snapshots”, on the average, each CCC snapshot consumed 5GB and each TM snapshot consumes 10GB.

"get information" shows my Macintosh HD consumed ~100GB. The first CCC and TM backup will consume ~100GB. Thus, the rest of storage can be used by snapshots. The number of snapshots before disk full is calculated in the following table against SSD capacity

SSD capacity	CCC with 5GB/Snapshot	Time Machine with 10GB/Snapshot
1TB	~180	~90
2TB	~400	~200
4TB	~800	~400

Table: maximum number of snapshots for CCC and TM before “disk full” occurs



If I use a 4TB Samsung SD for CCC, and use the above Thinning, the number of weekly snapshots will be 800-(360+90)=350 weekly snapshots, which will take 7 years before disk full.

For TM, the retention is: Hourly: 24 hours; Daily: 30 days; Weekly: till disk full.

Thus, I will have 400-(24+30)= 346 weekly snapshots , which will also take 7 years before disk full.

Is my calculation correct?

 

[gilby101]

"get information" shows my Macintosh HD consumed ~100GB. The first CCC and TM backup will consume ~100GB.

There are problems right back at your starting points.

Macintosh HD or Macintosh HD - Data? Also, not all files are backed up so I would expect the first backup to take somewhat less than the space consumed by the Macintosh HD - Data volume. Look and see what the first backup consumes after it has been done and before doing any other backups.

Using CCC “Volumes” and storage consumed by “Snapshots”, on the average, each CCC snapshot consumed 5GB and each TM snapshot consumes 10GB.

You need to be very careful about using the snapshot sizes as reported by CCC and Disk Utility. What CCC calls Size and DU calls Private Size is the space occupied by files unique to that snapshot. This is the space you would recover by deleting just that one snapshot. It does not include files added by that backup which are also present on later backups. So adding up the CCC Size of the snapshots does not tell you much about the total space consumed.

You will notice that older snapshots are reported as larger than new snapshots. As data is deleted by snapshots there is more that is unique to each remaining snapshot. For example on my CCC backup of my boot disk, the hourly snapshots are typically around 1GB, the daily snapshots around 2.5GB and monthly snapshots 30GB.

This makes any average size calculation of limited value. You will only gain (limited) knowledge of long term trends when you have a few snapshots in the longest time frame - e.g. weekly or monthly snapshots.

Comparing average sizes of TM and CCC snapshots is of limited value unless you have similar snapshot timing, thinning and long term history for each of them.

So I don't accept that your calculations are valid regarding long term trends.

If the sizes of TM and CCC backups differ significantly, you need to look at what is being (and not being) backed up.

 

[dai-leung]

Absorbing what you said. It will take me some sometime to understand.

For example on my CCC backup of my boot disk, the hourly snapshots are typically around 1GB, the daily snapshots around 2.5GB and monthly snapshots 30GB.

Any idea why snapshots grow in size over time. Will your yearly snapshots grow to 300GB?

 

[dai-leung]

You are correct, snapshots do grow in size. I don't understand this article ; it said:
"As that’s already over 24 hours old, it will grow steadily larger, as it retains deleted and changed file data from the more distant past. After a few days, that oldest snapshot may have grown to tens of GB in size......By that time, the snapshot could have exceeded 100 GB in size."

Understanding and managing Time Machine snapshots

Why Time Machine makes snapshots, and how they can grow and apparently consume free space. What you can and should do to manage this.

eclecticlight.co

Even though a snapshot size can grow over time, also there seems to be no way to check the size of a snapshot, however, the storage used by snapshots as reported by CCC seems to be accurate, but this storage size may become larger over time because the snapshot sizes are growing according to your post. Yes?

 

[gilby101]

Any idea why snapshots grow in size over time. Will your yearly snapshots grow to 300GB?

They seem to grow because of situations like: There is a file which only exits in two consecutive backups - so it is not included in the "size" ("private size" in DU) of either snapshot for which "size" only measures unique files. Delete one of the snapshots and the other now has an extra unique file, and so having a larger "size" based on the unique files it holds.

Every time a snapshot is deleted, the next older and next younger snapshot may increase in "size" as measured in this way. So I do know the "size" of the older snapshots will grow. How much - depends on the file modification/addition rate. Probably not 300GB in my case.

I do like that TM lists this measure of size as "private size" which makes me question what that might mean. CCC just calls it "size" - likely leading to an erroneous understanding of what is being measured. Bombich explains why in his support pages.

"As that’s already over 24 hours old, it will grow steadily larger, as it retains deleted and changed file data from the more distant past. After a few days, that oldest snapshot may have grown to tens of GB in size......By that time, the snapshot could have exceeded 100 GB in size."

Howard Oakley is at that point (and in most of that article) describing the snapshots made on the source volume - not the destination. These snapshots are purged (by TM) after 24 hours so long as hourly backups are being made, but can cause problems if you only do intermittent TM backups.

By default CCC also purges its source volume snapshots after 24 hours - but you can change that if you really need to.

 

[dai-leung]

Every time a snapshot is deleted, the next older and next younger snapshot may increase in "size" as measured in this way.

Other than deleting a snapshot will cause the next younger or older snapshot to grow in size, Howard Oakley pointed out there is another reason a snapshot size will grow (explained in a way I could understand).

“This is because they effectively consist of a copy of the APFS file system metadata, together with all the file data which has changed since that snapshot was made. This enables you to revert that volume to the exact state that it was in at the time that the snapshot was made. The further your volume departs from that state, the more disk data is required to return to that.” (https://eclecticlight.co/2020/02/06/orphaned-snapshots-a-growing-problem/)

Indeed, you are right. When I used CCC snapshot table to check the size (storage that would be released) of the CCC and TM snapshots , some (not all) of the oldest snapshots do grow to tens of GB.

What does the growing snapshots mean? I think that it means there will never be enough storage to keep old snapshots. I also think that very old snapshots probably not too useful (what is the use to restore to a state that was one or two years old? Meanwhile, the mac would have been updated to a newer version. “WE ARE NOT GOING BACK?) except the /Users folder (just like backup in ARQ). Perhaps CCC could offer a feature that will allows saving the /Users which will not grow in size and allow users to go back further back in time to search for and recover some old and forgotten files.

Perhaps, instead of CCC deletes the oldest weekly snapshot( tens of GB), it replaces it by its /Users (less than 100GB) folder. Thus, at the end of the snapshot table will be many /Users folders, all fits into budget.

It would be great to hear your view.

 

[dai-leung]

OCLP, CCC, Time Machine Snapshots, Migration Assistant.

Recently I updated to OCLP 1.5.0 and macOS 14.7. Found that when restore using a CCC or TM snapshot that was made in the older versions, would cause the computer not able to boot. Likewise, migration assistant using the same older version snapshot would not boot as well. In other words, all the snapshots I had make for the past several months become useless. Not sure if this just me doing something wrong.