Mariadb start failed in CentOS 7 - mysql

Question

I am using Mariadb (mysql Ver 15.1 Distrib 5.5.40-MariaDB) in CentOS (CentOS Linux release 7.0.1406). I tried to restart Mariadb.
systemctl start mariadb
Job for mariadb.service failed. See 'systemctl status mariadb.service' and 'journalctl -xn' for details.
When I checked : /var/log/mysql-error.log as suggested by 'systemctl status mariadb.service'
170523 10:20:10 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
170523 10:20:10 [Warning] 'THREAD_CONCURRENCY' is deprecated and will be removed in a future release.
170523 10:20:10 [Warning] Changed limits: max_open_files: 1024 max_connections: 214 table_cache: 400
170523 10:20:10 InnoDB: The InnoDB memory heap is disabled
170523 10:20:10 InnoDB: Mutexes and rw_locks use GCC atomic builtins
170523 10:20:10 InnoDB: Compressed tables use zlib 1.2.7
170523 10:20:10 InnoDB: Using Linux native AIO
170523 10:20:11 InnoDB: Initializing buffer pool, size = 15.6G
170523 10:20:11 InnoDB: Completed initialization of buffer pool
170523 10:20:11 InnoDB: highest supported file format is Barracuda.
170523 10:20:12 InnoDB: Waiting for the background threads to start
170523 10:20:13 Percona XtraDB (http://www.percona.com) 5.5.40-MariaDB-36.1 started; log sequence number 5336723441509
170523 10:20:13 [Note] Plugin 'FEEDBACK' is disabled.
170523 10:20:13 [ERROR] /usr/libexec/mysqld: unknown variable 'extra-lsndir=/var/tmp'
170523 10:20:13 [ERROR] Aborting
170523 10:20:13 InnoDB: Starting shutdown...
170523 10:20:15 InnoDB: Shutdown completed; log sequence number 5336723441509
170523 10:20:15 [Note] /usr/libexec/mysqld: Shutdown complete
170523 10:20:15 mysqld_safe mysqld from pid file /var/lib/mysql/master.compare-prices.repchecker.jp.pid ended
170523 10:21:10 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
170523 10:21:10 [Warning] 'THREAD_CONCURRENCY' is deprecated and will be removed in a future release.
170523 10:21:10 [Warning] Changed limits: max_open_files: 1024 max_connections: 214 table_cache: 400
170523 10:21:10 InnoDB: The InnoDB memory heap is disabled
170523 10:21:10 InnoDB: Mutexes and rw_locks use GCC atomic builtins
170523 10:21:10 InnoDB: Compressed tables use zlib 1.2.7
170523 10:21:10 InnoDB: Using Linux native AIO
170523 10:21:10 InnoDB: Initializing buffer pool, size = 15.6G
170523 10:21:11 InnoDB: Completed initialization of buffer pool
170523 10:21:11 InnoDB: highest supported file format is Barracuda.
170523 10:21:12 InnoDB: Waiting for the background threads to start
170523 10:21:13 Percona XtraDB (http://www.percona.com) 5.5.40-MariaDB-36.1 started; log sequence number 5336723441509
170523 10:21:13 [Note] Plugin 'FEEDBACK' is disabled.
170523 10:21:13 [ERROR] /usr/libexec/mysqld: unknown variable 'extra-lsndir=/var/tmp'
170523 10:21:13 [ERROR] Aborting
.
.
.
.
PS: /var/lib/mysql directory is owned by mysql (there is one more directory mysql~ which is empty)
drwxr-xr-x 8 mysql mysql 4096 May 23 11:05 mysql
drwxr-xr-x. 3 mysql mysql 26 Feb 4 2015 mysql~
Please provide some suggestion. How can I restart my mariadb, I have important database under mariadb.

Answer 1

From the last line of error
[ERROR] /usr/libexec/mysqld: unknown variable 'extra-lsndir=/var/tmp'
It is clear that this variable is not known so try to comment it from /etc/my.cnf and try again.
# Point the following paths to different dedicated disks
tmpdir = /var/tmp
extra-lsndir = /var/tmp ------> Comment this line
target-dir=/var/tmp
I hope it will help.