Duplicity 0.6.22 restore fails with error code 21

Asked by Daniel Hobi

We are using Duplicity 0.6.22 on Ubuntu 10.04 LTS.
A full backup (571 GB) is procesed by duplicity (using symetrical encryption) to a mounted CIFS share with return code 0.

However, in the kern.log we see, during the time of the full backup, messages such as:
CIFS VFS: No response to cmd 47 mid 20561
CIFS VFS: Write2 ret -11, wrote 0

During the restore of this full backup duplicity fails with error code: 21 (= mismatched_hash)
A manual check of the encrypted duplicity volumes confirms that some (about 12) volumes are corrupt.

Our main question is: Why does duplicity not detect the CIFS problems underneath during the backup?

Daniel

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Revision history for this message
Kenneth Loafman (kenneth-loafman) said :
#1

If the OS does not return an error, duplicity will not see it. Since the
OS is not reporting those errors, it may be that they were retried
successfully. It's hard to tell from your message.

Do you have a log file of the run? If so, please post it after obscuring
any sensitive info.

On Fri, Mar 7, 2014 at 5:46 AM, Daniel Hobi <
<email address hidden>> wrote:

> New question #245129 on Duplicity:
> https://answers.launchpad.net/duplicity/+question/245129
>
> We are using Duplicity 0.6.22 on Ubuntu 10.04 LTS.
> A full backup (571 GB) is procesed by duplicity (using symetrical
> encryption) to a mounted CIFS share with return code 0.
>
> However, in the kern.log we see, during the time of the full backup,
> messages such as:
> CIFS VFS: No response to cmd 47 mid 20561
> CIFS VFS: Write2 ret -11, wrote 0
>
> During the restore of this full backup duplicity fails with error code: 21
> (= mismatched_hash)
> A manual check of the encrypted duplicity volumes confirms that some
> (about 12) volumes are corrupt.
>
> Our main question is: Why does duplicity not detect the CIFS problems
> underneath during the backup?
>
> Daniel
>
> --
> You received this question notification because you are a member of
> duplicity-team, which is an answer contact for Duplicity.
>
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> Mailing list: https://launchpad.net/~duplicity-team
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>

Revision history for this message
Daniel Hobi (daniel-hobi) said :
#2

We can confirm, that this is not a duplicity issue.

What caused the symptoms on our setup was:
- We are running 10.04 LTS
- We activated the unatteded security updates
- Unfortunately, this security update of smbfs was not on the machine (We think it should have been):
https://launchpad.net/ubuntu/lucid/+source/samba/2:3.4.7~dfsg-1ubuntu3.13
(We are still investigating why this didn't happen)

So what caused our problems was that the pkg smbfs (in Version 3.12) did not work properly in combination with the latest security updates.

Once we realized this, a manual upgrade of smbfs to 3.13 made the symptoms disappear:
- Backuptime is back to normal
- No more CIFS Messages in kern.log
- The backup files are not corrupt anymore

Daniel