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Deleting Older Backup Versions

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Beginner
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Hi all,

I have Acronis True Image 2018 set to delete version chains older than 180 days, but some backups in the chain goes all the way back to 2018, and I need storage space without deleting the entire backup. Could the chain be corrupted?

Thanks.

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#1

There is nothing so far indicating the chain is corrupted. The first thing I would do is to validate the backup - this may take some time. It does not mean that there is no corruption, only that some forms of corruption have been eliminated. If you can open the backup, either in ATI or via Explorer then the backup itself is unlikely to be corrupted.

In more recent versions of ATI you can do a selective cleanup using the Windows app. Not sure if it was available in ATI 2018, but easy to find out by selecting the backup task, clicking on the "v" symbol to the right of the backup task name, and there is an option "cleanup" you can then select backup chains to be removed. If this is not available, you can manually delete individual backup chains in Explorer. Once you have done so, validate the backup - click on ignore to all error messages. Once it has finished, do a new validate and all should be well.

Getting to the key problem, of why the automatic cleanup rules are not working, it is a hard to say what is causing the problem. I do not have time at the moment to guide you through the process of working out what is going on; hopefully someone else will be able to help out.

Ian

 

Legend
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#2

Rusty wrote:

I have Acronis True Image 2018 set to delete version chains older than 180 days, but some backups in the chain goes all the way back to 2018, and I need storage space without deleting the entire backup. Could the chain be corrupted?

What are your other backup settings to go with the above?

What type of backup is being made?  Disks & Partitions or Files & Folders?

What backup scheme being used?  Full only, Incremental or Differential?

If Incremental or Differential schemes, how many such files before a new Full backup is made?

How often is the backup task being run?  Daily, Weekly, Monthly?

All of the above can influence how automatic cleanup works.

Automatic cleanup only operates on completed backup version chains and then the rules only start counting the 180 days (for your settings) after a new version chain has been started by creating a new full backup file of the next chain.

Personally, I never use any 'age' related cleanup settings as this is too vague and difficult to predict how it will work etc.

My preference is to use 'Store no more than 2 recent version chains' for the majority of my backup tasks, as this enables me to know how much space each task needs on my backup drive for its files. 

Example: I use a Disk backup of my OS drive using Incremental files, creating a new Full backup after 5 incrementals, with an average chain size (1 Full + 5 Inc files) of about 100GB, so I know that I need to have at least around 300GB free space on my backup drive to allow for 2 complete chains (2 x Full + 10 Inc files) plus a further Full file to be stored and allow automatic cleanup to work correctly.  This works regardless of the schedule for the task and I will always have at least 1 full chain plus another partial chain available for recovery if needed.

Beginner
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Comments: 12

#3

Here is a snip of my settings and a snip of my current chain. The first full backup goes all the way back to late 2018...

 

 

Forgive my editing skills. I tried posting live images instead of links.

 

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Legend
Posts: 102
Comments: 22524

#4

Rusty, do you have either a screen shot or listing of the backup files showing the actual full file names and the date/time stamps?  Are the files shown in your current image the only files or are there more that are not shown?

How often is your backup being run?  Is it on a schedule or just run manually on demand?

Beginner
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Comments: 12

#5

Here is a better snip with details listed...

 

And here is a snip of another backup chain stored on the same backup drive. In essence, I have two backup files (chains) listed on M\ drive in separate folders...

 

 

All backups were created manually without the scheduler.

EDIT: The file in question passed a validation test.

Legend
Posts: 102
Comments: 22524

#6

Rusty, thanks for the file information.

The 180 days for automatic cleanup will start counting down from the date that your new 'Before reinstalling Windows_full_b2_s1_v1.tib' file was created on 12/11/2019 and would be performed when you run a further backup after the count gets to 0.

For the second backup, if using the same 180 days setting, then that hasn't started counting yet as you are still working with the initial backup version chain (b1) and the count only begins after the next b2 chain is started by a new full backup file.

This is why I never use this setting and stay with using 'Store no more than 2 recent chains'!

Beginner
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Comments: 12

#7

What would my recourse be? Manually delete unwanted backups via Windows Explorer? Wouldn't that corrupt the chain?

Legend
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#8

Rusty, if you do manually delete unwanted backups then you also need to run a validation for the task afterwards so that the database used by ATI to track the files gets reconciled with the true state of the remaining files.

The alternative is to change the automatic cleanup settings to either user a shorter period than the current 180 days such as 60 days, or else swap to using 'Store no more than 1 or 2 recent version chains' and also reduce the number of incrementals being created before a new full backup from 8 to 5.

What you must not do is delete any older incremental files unless you delete every incremental file that follows them!

Beginner
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Comments: 12

#9
Steve Smith wrote:
 

What you must not do is delete any older incremental files unless you delete every incremental file that follows them!

That will corrupt the chain if I don't remove later versions first?

Legend
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#10

If you delete any incremental files from a chain then any later incremental files are rendered useless as each file is based on the changes detected since the previous file was created.

So, if you have a backup chain consisting of an initial Full backup followed by 20 Incremental files and you delete file _inc_b1_s2_v1 then all further files are of no value because the chain is broken regardless of still having inc_b1_s3_v1 through _inc_b1_s21_v1 files.

Beginner
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Comments: 12

#11

Out of curiosity (before your last post), I cut and pasted five incremental files from the middle of the pack and moved them to another physical drive. I then ran a validation of the remaining files on M drive from within Acronis, and the chain passed validation.

Is the chain still corrupted?

If necessary, I can start over. I just hated to lose my most recent incremental backups, but things are not set in stone here.

Legend
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#12

Rusty, if you take out 5 incremental files from the middle of a backup chain, then that chain is broken from that point and cannot be used for recovery.

The validation success does not show that recovery is possible, only that the files remain unchanged (based on embedded checksum values within the file(s) and recalculation of same).

See the ATI 2018 User Guide section on Incremental backups:

Incremental method

The result of an incremental method backup operation (also known as incremental backup version) contains only those files which have been changed since the LAST BACKUP.

Example: Every day, you write one page of your document and back it up using the incremental method. Acronis True Image saves the new page every time you run backup.

Note: The first backup version you create always uses full method.

  • 1.tib—file of full backup version.
  • 2.tib, 3.tib, 4.tib—files of incremental backup versions.

Additional information

Incremental method is the most useful when you need frequent backup versions and the ability to roll back to a specific point in time. As a rule, incremental backup versions are considerably smaller than full or differential versions. On the other hand, incremental versions require more work for the program to provide recovery.

Recovery: In the example above, to recover the entire work from the 4.tib file, you need to have all the backup versions—1.tib, 2.tib, 3.tib, and 4.tib. Therefore, if you lose an incremental backup version or it becomes corrupted, all later incremental versions are unusable.

Beginner
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#13

Thanks, let me digest this, and I will post back later.

Beginner
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Comments: 12

#14

I restored the deleted backup files to their original location, and then I deleted about four or five of the most recent backup files in that chain. But before I could decide what to do next, days later, Acronis deleted the entire backup chain, and then the program created a full backup on 8-25-20.

Ironically, the backup created on 8-25-20 does not show in the Activity tab, but it is there because I fetched a few files from it.

 

Beginner
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Comments: 12

#15

Any more thoughts?

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#16

You may need to validate the backup to get back full activity.