Acronis True Image 2017 unwanted differential file Deletion

Ken, the first issue here is that KB 47159: Acronis Backup: How to Delete Backups is not dealing with ATI 2017 but with Acronis Backup 11.5 which is a completely different product with different rules etc.

I would recommend taking a read through the ATI 2017 User manual for a better general understanding of the product.

There is no direct option to delete unwanted differential backup files provided by ATI 2017 as the feature to 'Clean up versions' did not get introduced until ATI 2019 (if I remember correctly).

This means for deleting differential files, you would need to use Windows Explorer to do this, but you then should perform a Validation of your backup task that created the deleted files in order to reconcile the information that is held with an internal database with the new status of available files.  Validation will cause an error message to be shown for each deleted file, for which you should take the Ignore option (if shown) or else the Cancel option, and do this until the validation finishes.

Hi Steve,

You truly are a legend!

When I cannot understand something I always search this forum and see your answers to many members which are always clear and concise, much moreso than the on line manuals.

So thank you again for promptly clarifying my issues above.

Acronis 2017 is verifying the remaining files in the chain as I type :-) 

I have been reading through the correct manual you sent (would be handy if it's available in pdf form offline) and have another query if I may?

For this particular PC and backup, apx 80% of data is unchanged each month so I use Differential method to reduce backup time and keep fewer files than incremental. I have also selected the auto-cleanup option &

"Keep size of the backup no more than [defined size]" specifying max 1900GB for my 2TB external hard drive.

These settings I believe will result in creating a first FULL backup file then a new DIFF file each run on the program until the 1900GB total size is reached for this chain, but then will it delete all files and start again with a new FULL file, or delete all DIFF files keeping the first FULL file and just create 1 new DIFF file please?

Many thanks in advance.

Ken

Ken, the user guides are available in PDF format to download if needed but are also available on your local hard drive via the Help button in the ATI GUI.

As far as I understand, there are no cleanup options in any current version of ATI that would automatically delete just the oldest differential backup files!  This is because automatic cleanup works only on 'completed' backup version chains, and only after a new version chain has been created successfully by a new full backup file.  The logic here is that nothing gets deleted until after a new backup is made so as to not leave users with no backup at all!

From ATI 2019 onwards, Acronis have introduced a new option / feature for each backup task shown in the GUI, where you can use the 'Clean up versions' tool and manually remove unwanted backup files (such as your older differential files) via a GUI tool that also takes care of any references to the files in the database etc without needing to run validation.

I have never used the option to keep the size of backups below a set value and this doesn't work in ATI 2020 since the introduction of the new .tibx file format (ported from the business product side of Acronis).

I suspect that your backup would fail if you hit the 1900GB limit on your 2TB drive unless a new Full backup can fit in the available free space to allow automatic cleanup to run and delete all the files of the old version chain after the new full was created.

Hi Steve,

Thanks again for your further prompt and full response.

So if I understand you correctly, if I change the limit from 1900GB to say 1000GB and my FULL backup is 600GB, it will keep adding differential files (which will be many of them over many months) until the total of the FULL and all DIFF files add to 1000GB then it will create a new FULL e.g. 800GB and it should immediately delete all other files leaving the new FULL file and then start adding DIFF files etc. on the subsequent backups.

If so, that should work well for me.

Thanks for heads up on new ATI 2020 software feature. I guess there's other good reasons to upgrade sooner rather than later.

Brgds

Ken

Ken, personally I use the option to 'Store no more than X recent version chains' for my backup tasks as I find that this is much easier to understand and to work out how much space is needed etc.

Example:

If I have a backup that creates say 10 differentials then a new full backup, then one version chain is the sum of the size of those files (1 x full plus 10 x differentials).

So if I use 'Store no more than 2 recent version chains' I would need enough free space on my backup drive to keep 2 such chains, plus 1 more full backup files before the oldest chain of 11 files gets deleted.

The main downside of using differential files is that each new file will be larger than the one before because all changes since the initial full backup are captured each time.  This is not a major issue if the degree of change is fairly low but can be an issue when lots of changes occur and the differentials can become larger than the original full backup file!

Hi Steve,

Yes, all reasonings and methods fully understood. My DIFF files will likely be much less than the 20% of FULL backup size I mentioned and I have reasons for not wanting to avoid very long backups with the computer left on (air conditioning a large room in 36 degree heat over here in Cyprus etc.) .

Thanks for all your help again - I'm now fully informed :-)

Have a great evening.

Ken, glad to help with advice.  Whereabouts in Cyprus do you live (North or South)?  I spent 5 years living there at the Royal Signals camp near Famagusta back in the late '60's / early '70's and our daughter was born at the military hospital at Dekhelia, so lots of fond memories apart from the invasion in 74!

Hi Steve,

I had a weird feeling you were going to say you had history here! Maybe as your photo portrays a true upstanding forces type chap and also that there have been many personnel posted here over the years.

I'm actually in Limassol in the south, since 1993 (was in Wallasey near Liverpool before that).

Many changes here since 1993 besides joining EU, mainly good ones with great infrastruture. The government have always been switched on and they've been hot on the Covid-19 issue with a fast reaction and lockdown and hence a lot of freedom after achieving zero new cases.

Let me know if you intend to holiday here and I would gladly buy you a nice cold Keo beer or 3! :-)

Brgds

Ken

Sounds like you are well settled there Ken, I haven't been back after being flown out of Akrotiri during the coup in 74 though the wife might like to come back!  We went on to Singapore for a year before rejoining civvy street back here.  Good to know that Cyprus are doing better with the pandemic than many other countries (including the UK)!

Best wishes, Steve