Hi,
Every week or so, I get alert that my website is down.
I try to open my blog (WP) just to see that it’s really down.
I see: Error Establishing a Database Connection
I checked if there are any logs for MySql but I couldn’t find it under system logs. I don’t know why on earth mysql would fail. Didn’t update, didn’t change any settings…
Howdy,
Usually when I see MySQL fail, it’s due to memory constraints of the server.
What output do you see if you run this command:
dmesg | tail -50
Do you see any messages about memory/RAM issues, and services being killed?
-Eric
Hi Eric, thanks for your answer!
currently no, but I have restarted the server to fix the problem
Now I only see:
[92230.218839] BANDWIDTH_IN:IN=eth0 OUT= MAC=xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:f0:08:00 SRC=173.245.56.xxx DST=192.241.xxx.xxx LEN=52 TOS=0x00 PREC=0x00 TTL=54 ID=55104 DF PROTO=TCP SPT=13318 DPT=80 WINDOW=16 RES=0x00 ACK FIN URGP=0
and very similar messages mostly the same.
I will check next time when MySql will fail.
I was just wondering couple of things.
I come from win world and I assume that if something has failed, you have to restart the server, in this case this also helps but I heard that with linux you could just restart the service or something?
When installing virtualmin I chose low memory for my sql, how and when would I know that memory is problematic?
Is there a way I could set notifications if my sql fails?
Can I automate that if My Sql fails that server is restarted or service is restarted?
Is there anything I can do to lower memory footprint of the system?
Other than this problem, I am uber satsified with my vps/virtualmin
I was checking website speed with various tools and none of my freinds site match the speed of it. It’s really great adventure self hosting 
Howdy,
Yup, if MySQL fails, you only need to restart the MySQL service, you wouldn’t need to reboot.
How much memory do you have? You can determine that by running this command:
free -m
There are some monitoring and notification tools available in Webmin -> Other -> System and Server Status.
Also, there’s info on lowering the memory footprint here:
Hi Eric,
First of all thank your for our answers.
Post on low memory is really great and I will get down to it immediately!
Now about my problem.
Mysql failed on Friday.
Until now only thing going on in my mind was, should I really upgrade to next plan where 1GB RAM is included instead of 0,5GB.
Then I checked my cloudflare account and noticed that on Friday I had 3036 pageviews, usually I get from 300 - 400 per day, so perhaps I was DDoSed.
I am running wordpress with some plugins and that means that with every visit there are several sql queries (from wordpress + plugins) and that means that you are correct and that Mysql didn’t have enough memory causing it to fail.
Would you know what can I do to optimize my VPS for DDoS (or slashdot or similar effect)
Hi Eric,
I found it, like you said, under Webmin -> Other -> System and Server Status there is an option to run a command if monitor goes down. But which command should I enter in ubuntu LTS to restart mysql service?
This command can start the MySQL service on Ubuntu:
/etc/init.d/mysql start
Hello can anyone let me the know the issue which i am facing again and again on my live site ,
Error :
SQLSTATE [HY000] [2002] Can not connect to local MySQL server through socket ‘/var/run/mysqld/mysqld.sock’
My vps mysql server going down again and again , after restart mysql server site back to normal, after sometime site goes down , tried with multiple users
As mention in the above comments as for : dmesg | tail -50 , please check the attachment .
I have free space of 1.9 gb in real memory , Local disk space : 13.27 GB used, 39.25 GB total
Do we have any solution on this .
Just in case I missing something … is there really no way to look at MySQL logs in virtualmin (or webmin)?