Sometimes system troble occur by the disk space problem. we can check root cause by some command. Volume usage per partition Most used disk directory Under / Under /var/ Check journal file size Check size and delte files which are before 3 days

confirm authentication SELECT user, host, plugin FROM mysql.user;

cp /usr/share/zoneinfo/Asia/Tokyo /etc/localtime

check memory #free -t -htotal used free shared buff/cache availableMem: 983M 488M 121M 524K 373M 341MSwap: 0B 0B 0BTotal: 983M 488M 121M ・make 1GM swap files #dd if=/dev/zero of=/var/swap bs=1M count=1024#mkswap /var/swap#swapon /var/swap

root user is able to change root user password. sudo passwd root