[MDEV-22872] Issues unpacking backup with mbstream Created: 2020-06-11  Updated: 2021-01-20  Resolved: 2021-01-20

Status: Closed
Project: MariaDB Server
Component/s: Backup
Affects Version/s: 10.3.17
Fix Version/s: 10.3.17

Type: Bug Priority: Major
Reporter: Matej Žerovnik Assignee: Robert Bindar
Resolution: Not a Bug Votes: 0
Labels: None
Environment:

CentOS 8.x


 Description   

When extracting mbstream file, I get an error about missing folder where the original backup was located.

$ pwd
 
/var/lib/mysql/mysqldumps/
 
$ lz4 -d backup.stream.gz | mbstream  -x -C .
 
mbstream: Can't create directory '/opt/mariabackup/base/2020-06-09_03-00-01//' (Errcode: 2 "No such file or directory")
 
[00] 2020-06-11 12:40:31 mbstream: failed to create file.

If I manually create folder path, the content is extracted successfully and xtrabackup_info file is placed in the original backup folder.

$ ll /opt/mariabackup/base/2020-06-09_03-00-01/
 
total 4
 
-rw-r----- 1 root root 652 Jun 11 13:14 xtrabackup_info



 Comments   
Comment by Matej Žerovnik [ 2020-06-11 ]

@robertbindar, @Robert Bindar

Comment by Robert Bindar [ 2020-06-11 ]

Ack matejzero, thanks again! I will investigate and let you know.

Comment by Tim Yan [ 2020-10-12 ]

It seems the mbstream is reusing the --extra-lsndir value used in the original backup command line. If the location was a tmp directory and deleted, the mbstream will fail. It may also fail if you unpack the same backup file twice, because the xtrabackup_info will be there already.

The only info we found related to the tmp directory is in the xtrabackup_info itself and its copies.

Comment by Matej Žerovnik [ 2021-01-04 ]

Is there any news regarding a fix?

This is hurting us more and more and a quick feedback would be useful, so we know if we should wait or search for a different solution.

Thanks.

Comment by Robert Bindar [ 2021-01-20 ]

Hei Tim and Matej, very sorry for being unresponsive here, for some reason Jira didn't notify me for your messages. I have a quick instinct to say I merged myself a Pull Request fixing this issue a while ago, but it's probably in a newer MariaDB version. I'll investigate this tomorrow first thing in the morning.

Comment by Matej Žerovnik [ 2021-01-20 ]

I had a look on GitHub and noticed that there was indeed a commit into a newer version in 10.3 train. We upgraded to newer version and it works.

I don't know which version fixed it as I can't find the commit now.

Comment by Robert Bindar [ 2021-01-20 ]

Hey Matej, what a nice thing that the bug was solved for you with just upgrading. The contribution I was speaking about is: https://github.com/MariaDB/server/commit/c0db3fe6dabd2cb0df9bf532f54f9e8d233fa499
From what I can see it was merged from 10.3.19 upwards, so I'm guessing that's why you .17 version didn't have the bug fixed. Sorry again for the confusion and I hope the experience for you is a lot better with this bug not causing trouble anymore.

Comment by Robert Bindar [ 2021-01-20 ]

Closing this for now as it seems the issue was resolved. Feel free to reopen if the bug can be reproduced again. Thanks again for keeping an eye on this.

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