MySQL Job failed to start

问题:

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 ?

回答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.

回答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.

回答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 It is better to find what the real culprits (my.cnf editing mistake does happens, e.g. bad/outdated parameter suggestion during mysql tuning.)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

回答4:

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

回答5:

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

回答6:

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

回答7:

This line did solve the issue in my case,

sudo apt clean

回答8:

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.

1. Resize our VPS Server to higher Hard Disk size
2. Start MySQL, it works.
3. 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.)
4. Downgrade your VPS Server to previous package you was already using

回答9:

In my case, i do:

1. sudo nano /etc/mysql/my.cnf
2. search for bind names and IPs
3. remove the specific, and let only localhost 127.0.0.1 and the hostname

回答10:

In my case:

• restart server
• restart mysql
• create .socket in directory

回答11:

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