MySQL Job failed to start - mysql

Question

I'm on Kubuntu 12.04, and after installing mysql via an apt-get (mysql ver: 5.5.35), i'm trying to start mysql service, but I got this error:
sudo service mysql start
start: Job failed to start
So I googled this problem, it says i have to go to the /var/log/mysql/error.log
But my error.log file is empty :(
Then I checked the permissions
:
drwxr-s--- 2 mysql adm 4096 Apr 7 11:21 mysql
-rw-r----- 1 mysql adm 0 Apr 7 11:21 error.log
So I don't know what to do... Why this error ? Why is the error file empty ?

Answer 1

First make a backup of your /var/lib/mysql/ directory just to be safe.
sudo mkdir /home/<your username>/mysql/
cd /var/lib/mysql/
sudo cp * /home/<your username>/mysql/ -R
Next purge MySQL (this will remove php5-mysql and phpmyadmin as well as a number of other libraries so be prepared to re-install some items after this.
sudo apt-get purge mysql-server-5.1 mysql-common
Remove the folder /etc/mysql/ and it's contents
sudo rm /etc/mysql/ -R
Next check that your old database files are still in /var/lib/mysql/ if they are not then copy them back in to the folder then chown root:root
(only run these if the files are no longer there)
sudo mkdir /var/lib/mysql/
sudo chown root:root /var/lib/mysql/ -R
cd ~/mysql/
sudo cp * /var/lib/mysql/ -R
Next install mysql server
sudo apt-get install mysql-server
Finally re-install any missing packages like phpmyadmin and php5-mysql.

Answer 2

My problem was running out of memory. Digital ocean has great instruction for adding swap memory for Ubuntu: https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04
This solved the issue and enabled me to restart the Mysql that otherwise would not start.

Answer 3

Reinstallation will works because it will reset all the value to default. It is better to find what the real culprits (my.cnf editing mistake does happens, e.g. bad/outdated parameter suggestion during mysql tuning.)
Here is the mysql diagnosis if you suspect some value is wrong inside my.cnf : Run the mysqld to show you the results.
sudo -u mysql mysqld
Afterwards, fix all the my.cnf key error that pop out from the screen until mysqld startup successfully.
Then restart it using
sudo service mysql restart

Answer 4

In my case, it simply because the disk is full.
Just clear some disk space and restart and everything is fine.

Answer 5

In most cases, just purging the mysql-server package and re-installing it will do the job.
Run,
sudo apt-get purge mysql-server-5.1 mysql-common
followed by
sudo apt-get install mysql-server

Answer 6

This line did solve the issue in my case,
sudo apt clean

Answer 7

In my case, i do:
sudo nano /etc/mysql/my.cnf
search for bind names and IPs
remove the specific, and let only localhost 127.0.0.1 and the hostname

Answer 8

Check the file permissions, if edited
Fail:
$ sudo chmod 776 /etc/mysql/my.cnf
$ sudo service mysql restart
mysql stop/waiting
start: Job failed to start
Ok:
$ sudo chmod 774 /etc/mysql/my.cnf
$ sudo service mysql restart
stop: Unknown instance:
mysql start/running, process 9564

Answer 9

To help others who do not have a full disk to troubleshoot this problem, first inspect your error log (for me the path is given in my /etc/mysql/my.cnf file):
tail /var/log/mysql/error.log
My problem turned out to be a new IP address allocated after some network router reconfiguration, so I needed to change the bind-address variable.

Answer 10

In my case the problem was the /var/log disk full (check with df -h)
Just deleted some log files and mysql started, no big deal!

Answer 11

The given solution requires enough free HDD, the actual problem was the HDD memory shortage. So If you don't have an alternative server or free disk space, you need some other alternative.
I faced this error with my production server (Linode VPS) when I was running a bulk download into MySQL. Its not a proper solution but VERY QUICK FIX, which we often need in production to bring things UP FAST.
Resize our VPS Server to higher Hard Disk size
Start MySQL, it works.
Login to your MySQL instance and make appropriate adjustments that caused this error (e.g. remove some records, table, or take DB backup to your local machine that are not required at production, etc. After all you know, what caused this issue.)
Downgrade your VPS Server to previous package you was already using

Answer 12

In my case:
restart server
restart mysql
create .socket in directory

Answer 13

I had the same problem. But i discover that my hd is full.
$ sudo cat /var/log/upstart/mysql.log
/proc/self/fd/9: ERROR: The partition with /var/lib/mysql is too full!
So, I run
$ df -h
And I got the message
/dev/xvda1 7.8G 7.4G 0 100% /
Then I found out which folder was full by running the following command on the terminal
$ cd /var/www
$ for i in *; do echo $i; find $i |wc -l; done
This give me the number of files on each folder on /var/www. I logged into the folder with most files, and deleted some backup files, and i continued deleting useless files and cache files.
then I run $ sudo /etc/init.d/mysql start and it work again