It seems the MySQL server is down due to a full disk and possible InnoDB page corruption. Here's how to resolve it:

I am doing my best to provide a solution that you can follow to resolve your MySQL database crash. I think MySQL is down due to a full disk and possible corruption. Here's how to resolve it:

1. Free disk space: Clear space on the /data mount to allow MySQL to restart.

2. Check InnoDB corruption: Start MySQL with innodb_force_recovery in my.cnf (e.g., innodb_force_recovery = 1) and restart MySQL.

3. Backup data: If MySQL starts, immediately back up the data with mysqldump or Percona XtraBackup.

4. Restore if needed: If recovery fails, restore from the most recent backup.

5. Monitor disk usage: Ensure ongoing disk space management to avoid future issues.

I also found a helpful blog that might assist you in fixing the issue.