mysql無法啟動 ERROR 2002 - Linux

板上各位大家好

前言:
作業系統是Ubuntu，最近在學校打工幫忙維護Drupal的網頁
昨天接到說突然有網頁無法更新的情況
後來我要從後台使用者登入，server卻一直沒有回應
上網爬文過後嘗試了GRANT ALL PRIVILEGES ON databasename.* 指令
之後重新啟動mysql後 Server load 突然變很重，
Drupal現在就成線site off-line的狀態


後來我要從command-line連線mysql時
出現以下錯誤:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket
'/var/run/mysqld/mysqld.sock' (2)
telnet 發現 mysql 3306 沒有運作
然後/var/run/mysqld也是空的

上網爬文後發現別人的解決方法
1.重灌mysql，可是我怕一重灌mysql，Drupal會整個掛掉

2.有人說/var/lib/mysql站太多容量了，要減肥
可是這裡面都是資料庫的資料表，若要備份該如何下手?

還是能在/var/run/mysqld 底下新增mysqld.sock的檔案呢?
麻煩各位了
-------------------------------

+ set -e
+ basename /etc/init.d/mysql
+ INITSCRIPT=mysql
+ JOB=mysql
+ [ mysql = upstart-job ]
+ [ -z start ]
+ COMMAND=start
+ shift
+ [ -z ]
+ ECHO=echo
+ echo Rather than invoking init scripts through /etc/init.d, use the service(8)
Rather than invoking init scripts through /etc/init.d, use the service(8)
+ echo utility, e.g. service mysql start
utility, e.g. service mysql start
+ echo

+ echo Since the script you are attempting to invoke has been converted to an
Since the script you are attempting to invoke has been converted to an
+ echo Upstart job, you may also use the start(8) utility, e.g. start mysql
Upstart job, you may also use the start(8) utility, e.g. start mysql
+ awk /[0-9]$/ { print $NF }
+ status mysql
+ PID=
+ [ -z ]
+ [ start = stop ]
+ [ -n ]
+ [ -z ]
+ [ start = restart ]
+ start mysql
start: Job failed to start


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