@Andrei all the error messages I found were included in my original email, let me know how I can provide additional information if no one can reproduce the problem. I forgot to include [email protected], you can see my reply below.
---------- Forwarded message --------- From: bapt x <[email protected]> Date: Wed, 16 Oct 2019 at 10:35 Subject: Re: [Maria-discuss] database corrupted when switching from MySQL to MariaDB on Ubuntu 19.04 To: Gordan Bobic <[email protected]> Thanks for the information. It looks like I did everything properly since I was able to reproduce the problem several times with a clean install of Ubuntu 19.04 on VirtualBox. I think if someone else tries the steps I explained, he can reproduce the problem. Now it would be nice to know if there is a way to recover the data. If MariaDB was able to corrupt the data, there should be a way to reverse engineer the process and restore the data. Maybe a developer that knows well MariaDB upgrade system has a solution. On Wed, 16 Oct 2019 at 10:23, Gordan Bobic <[email protected]> wrote: > I don't know if it is recoverable but it sounds like you missed the step > of always needing a full, clean shutdown between upgrades with > innodb_fast_shutdown=0. Then you can delete ib_logfile*, and upgrade. > > On Wed, 16 Oct 2019, 09:19 bapt x, <[email protected]> wrote: > >> Hello, >> >> On Ubuntu 19.04, which uses packages mariadb-server 10.3.17 and >> mysql-server 5.7.27, I noticed that if I wanted to switch from MySQL to >> MariaDB, the database is corrupted and there is a complete data loss >> even if I switch back to MySQL. >> In the previous version of Ubuntu, switching from MySQL to MariaDB did >> not manage to import data automatically (unlike Debian) but at least it >> created a backup of the data in /var/lib/mysql-5.7/ folder which is not >> done anymore. >> >> Here is the error message I saw during install when trying to use the >> database corrupted by MariaDB and switching back to MySQL: >> "MySQL has been frozen to prevent damage to your system. Please see >> /etc/mysql/FROZEN for help." >> >> And in /var/log/mysql/error.log: >> "[ERROR] InnoDB: Unsupported redo log format. The redo log was created >> with MariaDB 10.3.17. Please follow the instructions >> athttp://dev.mysql.com/doc/refman/5.7/en/upgrading-downgrading.html"; >> >> I was able to reproduce the issue with a clean installation of Ubuntu >> 19.04 in VirtualBox. >> >> Do you know where the problem comes from and if it is possible to fix >> the binary data from */var/lib/mysql/* to make it work with either MySQL >> or MariaDB? >> It looks like MariaDB tried to convert the data ("[ERROR] InnoDB: >> Unsupported redo log format") but now it fails with both MySQL and MariaDB. >> Is it possible to revert the changes done by MariaDB to make the data >> work again with MySQL? (and then do a proper backup with mysqldump) >> >> Thanks. >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~maria-discuss >> Post to : [email protected] >> Unsubscribe : https://launchpad.net/~maria-discuss >> More help : https://help.launchpad.net/ListHelp >> >
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