Can lost database somehow be recovered from files in /data?

Server
1

Environment: Debian 10 / mariadb-server 10.3.23 / owncloud-files 10.5.0

Hi all,

For some reason, mariadb-backup package got uninstalled without me noticing it
(i.e. the error raised by my nightly backup script).
Unfortunately, because of subsequent filesystem corruption on my master RAID,
I completely lost my owncloud database.
(My mariadb-backup based script produced empty backups on my backup RAID).

Now, can the database somehow (partly) be recovered from the files in /data?
I know I could lose a lot of information like versions, access rights, link shares etc.
Anyway, I would like to recover as much as possible automatically …

Thanks, Christian

P.S.
Would the below be a solution?

sudo -u www-data php occ maintenance:singleuser --on
sudo -u www-data php occ files:scan --all --repair
sudo -u www-data php occ maintenance:singleuser --off
2

That’s IMHO completely useless. I might be wrong, but if you don’t have a backup of your db (sqldump), you have to reinstall. This will perform scanning of your existing files anyway.

1 Like
3

That would be fantastic – are you sure about that?

4

Yes, at least for the initial (admin) user. For additional users it might fail, as their accounts do not exist yet. But here would manual scanning help, I guess.

1 Like
5

You convinced me – I’ll give it a try … just backed up /var/lib/mysql* and did
sudo apt install --reinstall mariadb-server-10.3
sudo apt install --reinstall mariadb-server-core-10.3
– both successful, mysql services now start again … :slight_smile:

Now backing up /var/www/owncloud (this will take some time), then will do
sudo apt install --reinstall owncloud-files
– fingers crossed … :crossed_fingers:

6

Serious trouble – was able to recreate MySQL database and MySQL user; however, no tables, no indexes, …

7

cfocke
Can lost database somehow be recovered from files in /data?

No. When you don’t have got a database backup you cannot recover your instance.

I’d suggest to

  • create a completely new instance.
  • after setup create the very same users as in your prior instance.
  • only then copy the user files to their new data directories.
  • after copying run
    sudo -u www-data php occ files:scan --all

Note that you’ll loose

  • all user passwords
  • all user and application settings
  • all shares
  • status of enabled/disabled apps

Maybe now is a good time to plan your future db backups :wink:

1 Like
9

Hi,
That’s exactly what I considered as last option, will do so.
Yes, and I will setup a monitoring for the database backup.
Thanks

10

Works – just had to rename /config/config.php to successfully run

sudo -u www-data php occ maintenance:install

Then created a user for my girlfriend and scanned her files for a test,
now doing the same for my own user and files (this will take some time …)

P.S.
Could leave all files in /data in place, were not affected by re-installation.

1 Like