インストール後にmysqlを起動できません

このガイドを使用して、Manjaro LinuxコンピュータにWordPressをインストールしようとしています。ここしかし、mysqlに問題があるのでうまくインストールされますが、起動しようとすると次のエラーが発生します。

sudo systemctl start mysqld
Job for mariadb.service failed because the control process exited with error code.
See "systemctl status mariadb.service" and "journalctl -xe" for details.

。

   journalctl -xe
    -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
    -- 
    -- Unit mariadb.service has begun starting up.
    Jul 14 20:42:35 mysqld[27759]: 2017-07-14 20:42:35 140483429396416 [Note] /usr/bin/mysqld (mysqld 10.1.24-Mari
    Jul 14 20:42:35 mysqld[27759]: 2017-07-14 20:42:35 140483429396416 [Warning] Can't create test file /var/lib/mysql/MyPC.lower-test
    Jul 14 20:42:35 mysqld[27759]: [89B blob data]
    Jul 14 20:42:35 mysqld[27759]: 2017-07-14 20:42:35 140483429396416 [ERROR] Aborting
    Jul 14 20:42:35 sudo[27697]: pam_unix(sudo:session): session closed for user root
    Jul 14 20:42:35 systemd[1]: mariadb.service: Main process exited, code=exited, status=1/FAILURE
    Jul 14 20:42:35 systemd[1]: Failed to start MariaDB database server.
    -- Subject: Unit mariadb.service has failed
    -- Defined-By: systemd
    -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
    -- 
    -- Unit mariadb.service has failed.
    -- 
    -- The result is failed.
    Jul 14 20:42:35 systemd[1]: mariadb.service: Unit entered failed state.
    Jul 14 20:42:35 systemd[1]: mariadb.service: Failed with result 'exit-code'.

。

    systemctl status mariadb.service
● mariadb.service - MariaDB database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; disabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Fri 2017-07-14 20:42:35 CDT; 13min ago
  Process: 27759 ExecStart=/usr/bin/mysqld $MYSQLD_OPTS $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION (code=exited, status=1/FAIL
  Process: 27705 ExecStartPre=/bin/sh -c [ ! -e /usr/bin/galera_recovery ] && VAR= ||   VAR=`/usr/bin/galera_recovery`; [ $? -
  Process: 27700 ExecStartPre=/bin/sh -c systemctl unset-environment _WSREP_START_POSITION (code=exited, status=0/SUCCESS)
 Main PID: 27759 (code=exited, status=1/FAILURE)
   Status: "MariaDB server is down"

Jul 14 20:42:34 systemd[1]: Starting MariaDB database server...
Jul 14 20:42:35 mysqld[27759]: 2017-07-14 20:42:35 140483429396416 [Note] /usr/bin/mysqld (mysqld 10.1.24-Mari
Jul 14 20:42:35 systemd[1]: mariadb.service: Main process exited, code=exited, status=1/FAILURE
Jul 14 20:42:35 systemd[1]: Failed to start MariaDB database server.
Jul 14 20:42:35 systemd[1]: mariadb.service: Unit entered failed state.
Jul 14 20:42:35 systemd[1]: mariadb.service: Failed with result 'exit-code'.

。何が間違っているのか、どうすればいいのかわかりません。

新しいもの：

:26 140676675801024 [Note] /usr/bin/mysqld (mysqld 10.1.24-MariaDB) starting as process 15628 ...
:26 140676675801024 [Note] InnoDB: innodb_empty_free_list_algorithm has been changed to legacy because of small buffer pool si
:26 140676675801024 [Note] InnoDB: Using mutexes to ref count buffer pool pages
:26 140676675801024 [Note] InnoDB: The InnoDB memory heap is disabled
:26 140676675801024 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
:26 140676675801024 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
:26 140676675801024 [Note] InnoDB: Compressed tables use zlib 1.2.11
:26 140676675801024 [Note] InnoDB: Using Linux native AIO
:26 140676675801024 [Note] InnoDB: Using SSE crc32 instructions
:26 140676675801024 [Note] InnoDB: Initializing buffer pool, size = 128.0M
:26 140676675801024 [Note] InnoDB: Completed initialization of buffer pool
:26 140676675801024 [Note] InnoDB: Highest supported file format is Barracuda.
:26 140676675801024 [Note] InnoDB: 128 rollback segment(s) are active.
:26 140676675801024 [Note] InnoDB: Waiting for purge to start
:26 140676675801024 [Note] InnoDB:  Percona XtraDB (http://www.percona.com) 5.6.36-82.0 started; log sequence number 1600709
:26 140676675801024 [Note] Plugin 'FEEDBACK' is disabled.
:26 140676069496576 [Note] InnoDB: Dumping buffer pool(s) not yet started
:26 140676675801024 [ERROR] Could not open mysql.plugin table. Some plugins may be not loaded
:26 140676675738368 [Warning] Failed to load slave replication state from table mysql.gtid_slave_pos: 1146: Table 'mysql.gtid_slave_pos: 1146: Table 'mysql.gtid_slave_pos' doesn't exist
:26 140676675801024 [ERROR] Can't open and lock privilege tables: Table 'mysql.servers' doesn't exist
:26 140676675801024 [Note] Server socket created on IP: '::'.
:26 140676675801024 [ERROR] Can't start server: Bind on TCP/IP port. Got error: 98: Address already in use
:26 140676675801024 [ERROR] Do you already have another mysqld server running on port: 3306 ?
:26 140676675801024 [ERROR] Aborting
Jul 16 21:12:29 MyPc systemd[1]: mariadb.service: Main process exited, code=exited, status=1/FAILURE
Jul 16 21:12:29 MyPc systemd[1]: Failed to start MariaDB database server.
-- Subject: Unit mariadb.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit mariadb.service has failed.
-- 
-- The result is failed.
Jul 16 21:12:29 MyPc systemd[1]: mariadb.service: Unit entered failed state.
Jul 16 21:12:29 MyPc systemd[1]: mariadb.service: Failed with result 'exit-code'.
lines 3172-3190/3190 (END)

詳細:

:39 139642281652160 [Note] /usr/bin/mysqld (mysqld 10.1.24-MariaDB) starting as process 17168 ...
:39 139642281652160 [Note] InnoDB: innodb_empty_free_list_algorithm has been changed to legacy because of small buffer pool si
:39 139642281652160 [Note] InnoDB: Using mutexes to ref count buffer pool pages
:39 139642281652160 [Note] InnoDB: The InnoDB memory heap is disabled
:39 139642281652160 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
:39 139642281652160 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
:39 139642281652160 [Note] InnoDB: Compressed tables use zlib 1.2.11
:39 139642281652160 [Note] InnoDB: Using Linux native AIO
:39 139642281652160 [Note] InnoDB: Using SSE crc32 instructions
:39 139642281652160 [Note] InnoDB: Initializing buffer pool, size = 128.0M
:39 139642281652160 [Note] InnoDB: Completed initialization of buffer pool
:39 139642281652160 [Note] InnoDB: Highest supported file format is Barracuda.
:39 139642281652160 [Note] InnoDB: 128 rollback segment(s) are active.
:39 139642281652160 [Note] InnoDB: Waiting for purge to start
:39 139642281652160 [Note] InnoDB:  Percona XtraDB (http://www.percona.com) 5.6.36-82.0 started; log sequence number 1600719
:39 139641681639168 [Note] InnoDB: Dumping buffer pool(s) not yet started
:39 139642281652160 [Note] Plugin 'FEEDBACK' is disabled.
:39 139642281652160 [ERROR] Could not open mysql.plugin table. Some plugins may be not loaded
:39 139642281589504 [Warning] Failed to load slave replication state from table mysql.gtid_slave_pos: 1146: Table 'mysql.gtid_
:39 139642281652160 [Note] /usr/bin/mysqld (mysqld 10.1.24-MariaDB) starting as process 17168 ...
:39 139642281652160 [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.
:39 139642281652160 [Note] InnoDB: Using mutexes to ref count buffer pool pages
:39 139642281652160 [Note] InnoDB: The InnoDB memory heap is disabled
:39 139642281652160 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
:39 139642281652160 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
:39 139642281652160 [Note] InnoDB: Compressed tables use zlib 1.2.11
:39 139642281652160 [Note] InnoDB: Using Linux native AIO
:39 139642281652160 [Note] InnoDB: Using SSE crc32 instructions
:39 139642281652160 [Note] InnoDB: Initializing buffer pool, size = 128.0M
:39 139642281652160 [Note] InnoDB: Completed initialization of buffer pool
:39 139642281652160 [Note] InnoDB: Highest supported file format is Barracuda.
:39 139642281652160 [Note] InnoDB: 128 rollback segment(s) are active.
:39 139642281652160 [Note] InnoDB: Waiting for purge to start
:39 139642281652160 [Note] InnoDB:  Percona XtraDB (http://www.percona.com) 5.6.36-82.0 started; log sequence number 1600719
:39 139641681639168 [Note] InnoDB: Dumping buffer pool(s) not yet started
:39 139642281652160 [Note] Plugin 'FEEDBACK' is disabled.
:39 139642281652160 [ERROR] Could not open mysql.plugin table. Some plugins may be not loaded
:39 139642281589504 [Warning] Failed to load slave replication state from table mysql.gtid_slave_pos: 1146: Table 'mysql.gtid_slave_pos' doesn't exist