Database server is down

I have a problem the Database server is down. Free disk space is half the disk. I can not restart it from SSH. Please help me!

service mysql status
ERROR! MariaDB is not running, but lock file (/var/lock/subsys/mysql) exists

systemctl status mysql.service

● mysql.service - LSB: start and stop MariaDB
Loaded: loaded (/etc/rc.d/init.d/mysql; bad; vendor preset: disabled)
Active: failed (Result: exit-code) since Tue 2020-02-18 10:50:55 UTC; 8s ago
Docs: man:systemd-sysv-generator(8)
Process: 15616 ExecStart=/etc/rc.d/init.d/mysql start (code=exited, status=1/FAILURE)

Feb 18 10:50:53 localhost systemd[1]: Starting LSB: start and stop MariaDB…
Feb 18 10:50:54 localhost mysql[15616]: Starting MariaDB.200218 10:50:54 mysqld_safe Logging to ‘/var/lib/mysql/localhost.err’.
Feb 18 10:50:54 localhost mysql[15616]: 200218 10:50:54 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
Feb 18 10:50:55 localhost mysql[15616]: /etc/rc.d/init.d/mysql: line 262: kill: (15621) - No such process
Feb 18 10:50:55 localhost mysql[15616]: ERROR!
Feb 18 10:50:55 localhost systemd[1]: mysql.service: control process exited, code=exited status=1
Feb 18 10:50:55 localhost systemd[1]: Failed to start LSB: start and stop MariaDB.
Feb 18 10:50:55 localhost systemd[1]: Unit mysql.service entered failed state.
Feb 18 10:50:55 localhost systemd[1]: mysql.service failed.

Try this to get more a more detailed log output: Unable to start mysql - no such process | Linode Questions

service mysql start

Starting MariaDB.200218 13:55:05 mysqld_safe Logging to ‘/var/lib/mysql/localhost.err’.
200218 13:55:05 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
/etc/init.d/mysql: line 262: kill: (24625) - No such process
ERROR!

in phpmyadmin
mysqli::real_connect(): (HY000/2002): Connection refused

Server Error Log in OLS
[PlainConf] [httpServerConfig:] Not support [adminroot $SERVER_ROOT/admin/] in file /usr/local/lsws/conf/httpd_config.conf:16

2020-02-18 09:55:58 7fa34d5f98c0 InnoDB: Assertion failure in thread 140339354507456 in file buf0buf.cc line 4511
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to https://jira.mariadb.org/
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: MySQL :: MySQL 5.6 Reference Manual :: 14.21.2 Forcing InnoDB Recovery
InnoDB: about forcing recovery.
200218 9:55:58 [ERROR] mysqld got signal 6 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.

To report this bug, see MariaDB Community Bug Reporting - MariaDB Knowledge Base

We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed,
something is definitely wrong and this may fail.

Server version: 10.0.38-MariaDB-wsrep
key_buffer_size=134217728
read_buffer_size=131072
max_used_connections=0
max_threads=153
thread_count=0
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 467095 K bytes of memory
Hope that’s ok; if not, decrease some variables in the equation.

Thread pointer: 0x0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong…
stack_bottom = 0x0 thread_stack 0x48000
/usr/sbin/mysqld(my_print_stacktrace+0x2e)[0xbf35fe]
/usr/sbin/mysqld(handle_fatal_signal+0x3b6)[0x75f406]
sigaction.c:0(__restore_rt)[0x7ff79b9365f0]
:0(__GI_raise)[0x7ff79a05e337]
:0(__GI_abort)[0x7ff79a05fa28]
/usr/sbin/mysqld[0xae06f2]
/usr/sbin/mysqld[0xaf6af1]
/usr/sbin/mysqld[0xadce4b]
/usr/sbin/mysqld[0xa98858]
/usr/sbin/mysqld[0xa82c4b]
/usr/sbin/mysqld[0x9b45fc]
/usr/sbin/mysqld(_Z24ha_initialize_handlertonP13st_plugin_int+0x5e)[0x7613ae]
/usr/sbin/mysqld[0x5f16f6]
/usr/sbin/mysqld(_Z11plugin_initPiPPci+0x494)[0x5f29c4]
/usr/sbin/mysqld[0x5442fc]
/usr/sbin/mysqld(_Z11mysqld_mainiPPc+0x90b)[0x548d7b]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x7ff79a04a505]
/usr/sbin/mysqld[0x53bc27]
The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains
information that should help you find out what is causing the crash.’
200218 10:14:14 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
200218 10:14:14 mysqld_safe WSREP: Running position recovery with --log_error=’/var/lib/mysql/wsrep_recovery.ivK3mr’ --pid-file=’/var/lib/mysql/localhost-recover.pid’
200218 10:14:14 [Note] /usr/sbin/mysqld (mysqld 10.0.38-MariaDB-wsrep) starting as process 48956 …
200218 10:14:15 mysqld_safe WSREP: Failed to recover position: '200218 10:14:14 [Note] InnoDB: innodb_empty_free_list_algorithm has been changed to legacy because of small buffer pool size. In order to use backoff, increase buffer pool at least up to 20MB.

200218 10:14:14 [Note] InnoDB: Using mutexes to ref count buffer pool pages
200218 10:14:14 [Note] InnoDB: The InnoDB memory heap is disabled
200218 10:14:14 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
200218 10:14:14 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
200218 10:14:14 [Note] InnoDB: Compressed tables use zlib 1.2.7
200218 10:14:14 [Note] InnoDB: Using Linux native AIO
200218 10:14:14 [Note] InnoDB: Using CPU crc32 instructions
200218 10:14:14 [Note] InnoDB: Initializing buffer pool, size = 128.0M
200218 10:14:14 [Note] InnoDB: Completed initialization of buffer pool
InnoDB: Database page corruption on disk or a failed
InnoDB: file read of page 5.
InnoDB: You may have to recover from a backup.
2020-02-18 10:14:14 7f018e8508c0 InnoDB: Page dump in ascii and hex (16384 bytes):

df
Filesystem 1K-blocks Used Available Use% Mounted on
devtmpfs 3983228 0 3983228 0% /dev
tmpfs 3995008 152 3994856 1% /dev/shm
tmpfs 3995008 86380 3908628 3% /run
tmpfs 3995008 0 3995008 0% /sys/fs/cgroup
/dev/mapper/centos-root 80726016 36750152 43975864 46% /
/dev/loop0 1479088 57504 1328400 5% /tmp
/dev/sda1 1038336 362968 675368 35% /boot
tmpfs 799004 0 799004 0% /run/user/0

See for yourself, it seems ok

Also
systemctl start pdns.service
Is not starting anymore either

is that openvz ?