How to check backup (increment) integrity?

Asked by ardabro on 2017-09-12

Is there any way to check integrity of backup files?
I don't mean verification with comparison to original files.
I mean integrity test without touching source folder, i.e check whether any backup file is corrupted.
The only way that came to my mind is restore with --dry-run but it'll check the whole backup and may last for ages.
How to check integrity of certain increment? Is there any possibility?

Question information

Language:
English Edit question
Status:
Solved
For:
Duplicity Edit question
Assignee:
No assignee Edit question
Solved by:
ardabro
Solved:
2017-09-20
Last query:
2017-09-20
Last reply:
2017-09-15
edso (ed.so) said : #1

On 9/12/2017 22:58, ardabro wrote:
> New question #657939 on Duplicity:
> https://answers.launchpad.net/duplicity/+question/657939
>
> Is there any way to check integrity of backup files?
> I don't mean verification with comparison to original files.

verify does not compare to the source files since some time unless you give he --compare-data parameter.

> I mean integrity test without touching source folder, i.e check whether any backup file is corrupted.
> The only way that came to my mind is restore with --dry-run but it'll check the whole backup and may last for ages.
> How to check integrity of certain increment? Is there any possibility?

no. as increments depend on earlier backups all those will be used as well. from the man page

"
verify [--compare-data] [--time <time>] [--file-to-restore <rel_path>] <url> <local_path>
Restore backup contents temporarily file by file and compare against the local path’s contents. duplicity will exit with a non-zero error level if any files are different. On verbosity level info (4) or higher, a message for each file that has changed will be logged.
The --file-to-restore option restricts verify to that file or folder. The --time option allows to select a backup to verify against. The --compare-data option enables data comparison (see below).
"

it should be updated that data comparison is not the default anymore although the local_path is still obligatory. somebody needs to find the time to clean that out
.

..ede/duply.net

ardabro (ardabro) said : #2

Ok, but this doen't answer my question. I don't want to check backup contents. I want to check compressed and encrypted files integrity, without accessing source folder.

edso (ed.so) said : #3

you can!

using a recent duplicity it will ignore <local_path> (whule still needed) and simply check if the backup is restorable.. ede/duply.net

ardabro (ardabro) said : #4

The necessity of giving fake-source path for verification is very confusing idea but OK. Thanks

edso (ed.so) said : #5

On 9/20/2017 22:34, ardabro wrote:
> Question #657939 on Duplicity changed:
> https://answers.launchpad.net/duplicity/+question/657939
>
> Status: Answered => Solved
>
> ardabro confirmed that the question is solved:
> The necessity of giving fake-source path for verification is very
> confusing idea but OK. Thanks
>

it's legacy. previously the restored files meta data was _always_ compared to the local source, hence the need for the parameter.
as i wrote, somebody needs to take care of it. nobody did so far.

..ede/duply.net