What could be causing MariaDB 10.2 to crash?

Question

MySQL

I can not understand in any way why the DB fell.

[email protected]:~# systemctl status mariadb.service
● mariadb.service - MariaDB database server
   Loaded: loaded (/lib/systemd/system/mariadb.service; enabled)
  Drop-In: /etc/systemd/system/mariadb.service.d
           └─migrated-from-my.cnf-settings.conf
   Active: failed (Result: timeout) since Sun 2017-10-08 01:51:00 MSK; 9h ago
  Process: 636 ExecStart=/usr/sbin/mysqld $MYSQLD_OPTS $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION (code=exited, status=0/SUCCESS)
  Process: 480 ExecStartPre=/bin/sh -c [ ! -e /usr/bin/galera_recovery ] && VAR= ||   VAR=`/usr/bin/galera_recovery`; [ $? -eq 0 ]   && systemctl set-environm
ent _WSREP_START_POSITION=$VAR || exit 1 (code=exited, status=0/SUCCESS)
  Process: 474 ExecStartPre=/bin/sh -c systemctl unset-environment _WSREP_START_POSITION (code=exited, status=0/SUCCESS)
  Process: 449 ExecStartPre=/usr/bin/install -m 755 -o mysql -g root -d /var/run/mysqld (code=exited, status=0/SUCCESS)
 Main PID: 636 (code=exited, status=0/SUCCESS)
   Status: "MariaDB server is down"

Oct 08 01:50:58 debian mysqld[636]: 2017-10-08  1:50:58 140157871458048 [Note] Event Scheduler: Purging the queue. 0 events
Oct 08 01:50:58 debian mysqld[636]: 2017-10-08  1:50:58 140157164435200 [Note] InnoDB: FTS optimize thread exiting.
Oct 08 01:50:58 debian mysqld[636]: 2017-10-08  1:50:58 140157871458048 [Note] InnoDB: Starting shutdown...
Oct 08 01:50:58 debian mysqld[636]: 2017-10-08  1:50:58 140157047002880 [Note] InnoDB: Dumping buffer pool(s) to /var/lib/mysql/ib_buffer_pool
Oct 08 01:50:58 debian mysqld[636]: 2017-10-08  1:50:58 140157047002880 [Note] InnoDB: Buffer pool(s) dump completed at 171008  1:50:58
Oct 08 01:51:00 debian mysqld[636]: 2017-10-08  1:51:00 140157871458048 [Note] InnoDB: Shutdown completed; log sequence number 1841482
Oct 08 01:51:00 debian mysqld[636]: 2017-10-08  1:51:00 140157871458048 [Note] InnoDB: Removed temporary tablespace data file: "ibtmp1"
Oct 08 01:51:00 debian mysqld[636]: 2017-10-08  1:51:00 140157871458048 [Note] /usr/sbin/mysqld: Shutdown complete
Oct 08 01:51:00 debian systemd[1]: Failed to start MariaDB database server.
Oct 08 01:51:00 debian systemd[1]: Unit mariadb.service entered failed state.

Answer 1

It happens with us when a client for some reason reboots a server with no free space through the billing panel.
Usually the problem is in the /var/lib/mysql/tc.log file - rename it. MariaDB should create a new one on start

Answer 2

Most likely some kind of table.
Add the log_error option to the mysqld section in the /etc/mysql/my.cnf configuration file (if it is not there), perhaps the file will be different, for example

[mysqld]
...
log_error = /var/log/mysql_error.log
...

and restart maria
then check the log for errors