БД Percona не запускается: initscript mysql, сбой действия «start»

После того, как я установил сервер Percona, я получил это сообщение:

 * Percona Server is distributed with several useful UDF (User Defined Function) from Percona Toolkit.
 * Run the following commands to create these functions:

    mysql -e "CREATE FUNCTION fnv1a_64 RETURNS INTEGER SONAME 'libfnv1a_udf.so'"
    mysql -e "CREATE FUNCTION fnv_64 RETURNS INTEGER SONAME 'libfnv_udf.so'"
    mysql -e "CREATE FUNCTION murmur_hash RETURNS INTEGER SONAME 'libmurmur_udf.so'"

 * See http://www.percona.com/doc/percona-server/5.6/management/udf_percona_toolkit.html for more details

Job for mysql.service failed. See "systemctl status mysql.service" and "journalctl -xe" for details.
invoke-rc.d: initscript mysql, action "start" failed.
dpkg: error processing package percona-server-server-5.6 (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of percona-server-server:
 percona-server-server depends on percona-server-server-5.6; however:
  Package percona-server-server-5.6 is not configured yet.

dpkg: error processing package percona-server-server (--configure):
 dependency problems - leaving unconfigured
Processing triggers for libc-bin (2.21-0ubuntu4) ...
Errors were encountered while processing:
 percona-server-server-5.6
 percona-server-server
E: Sub-process /usr/bin/dpkg returned an error code (1)
root@public-server-01:~/src# systemctl status mysql.service
● mysql.service - LSB: Start and stop the mysql (Percona Server) daemon
   Loaded: loaded (/etc/init.d/mysql)
   Active: failed (Result: exit-code) since Wed 2015-09-30 04:26:52 UTC; 38min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 20916 ExecStart=/etc/init.d/mysql start (code=exited, status=1/FAILURE)

Sep 30 04:26:41 public-server-01 systemd[1]: Starting LSB: Start and stop the mysql (Percona Server) daemon...
Sep 30 04:26:41 public-server-01 mysql[20916]: * Starting MySQL (Percona Server) database server mysqld
Sep 30 04:26:52 public-server-01 systemd[1]: mysql.service: control process exited, code=exited status=1
Sep 30 04:26:52 public-server-01 systemd[1]: Failed to start LSB: Start and stop the mysql (Percona Server) daemon.
Sep 30 04:26:52 public-server-01 systemd[1]: Unit mysql.service entered failed state.
Sep 30 04:26:52 public-server-01 mysql[20916]: ...fail!
Sep 30 04:26:52 public-server-01 systemd[1]: mysql.service failed.

Не понимаю, почему не запускается.

Я использую Ubuntu 15. 1 ГБ оперативной памяти ...