Question

Mysql keeps crashing (Kill process 919 (mysqld) score 86 or sacrifice child)

  • Posted on August 29, 2014
  • evgenyAsked by Evgeny

I’m using wordpress on ubuntu (standard offer, didn’t change any seetings) on minimal configuration (512 MB). New, small blog, just 1 page and 2 posts. Maximum pageviews per day - 156 (yesterday).

Today in the morning I’ve found it doesn’t work. The reason is that mysql is down. I’ve restarted linux. The only visitor was me. But after short time mysql was down again (there were no visitors except me, so not big load). It repeated several times.

Later I’ve created 1GB swap file. For some time it was ok. So I thought that problem was solved. But later I found that mysql was down again. So 1,5 GB is not enough?

It seems like apache eats a lot of memory at some point. But I’m not sure.

Did anyone experience the same problem? Should I change any apache or mysql settings? I thought standard offer by DigitalOcean should work properly.

Here is the part of mysql error.log during crash:

140829 23:12:04 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead. 140829 23:12:04 [Note] Plugin ‘FEDERATED’ is disabled. 140829 23:12:04 InnoDB: The InnoDB memory heap is disabled 140829 23:12:04 InnoDB: Mutexes and rw_locks use GCC atomic builtins 140829 23:12:04 InnoDB: Compressed tables use zlib 1.2.8 140829 23:12:04 InnoDB: Using Linux native AIO 140829 23:12:04 InnoDB: Initializing buffer pool, size = 128.0M InnoDB: mmap(137363456 bytes) failed; errno 12 140829 23:12:04 InnoDB: Completed initialization of buffer pool 140829 23:12:04 InnoDB: Fatal error: cannot allocate memory for the buffer pool 140829 23:12:04 [ERROR] Plugin ‘InnoDB’ init function returned error. 140829 23:12:04 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed. 140829 23:12:04 [ERROR] Unknown/unsupported storage engine: InnoDB 140829 23:12:04 [ERROR] Aborting

140829 23:12:04 [Note] /usr/sbin/mysqld: Shutdown complete


Submit an answer


This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

Sign In or Sign Up to Answer

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

Accepted Answer

The reason was an XML-RPC attack. Here you can find an article about how to protect you WordPress site: https://www.digitalocean.com/community/tutorials/how-to-protect-wordpress-from-xml-rpc-attacks-on-ubuntu-14-04

P.S. Sorry for keeping silence. I just did’t use my DigitalOcean account for a long time:)

alexdo
Site Moderator
Site Moderator badge
October 23, 2020

Hello, all

The key error here is:

InnoDB: Fatal error: cannot allocate memory for the buffer pool

This crash is due to your system running out of memory. I’d suggest that you add a swap file to give yourself a bit more of a buffer. Check out this tutorial:

How To Add Swap on Ubuntu 14.04

What you can also do is to use the MySQLTuner script.

The MySQLTuner is a script written in Perl and allows you to quickly test your MySQL configuration and it gives you suggestions for adjustments to increase performance and stability.

According to the official GitHub page, it supports 300 indicators for MySQL/MariaDB/Percona Server in this last version.

To run the script you could do the following:

  • SSH to your Droplet
  • Download the script:
wget http://mysqltuner.pl/ -O mysqltuner.pl
  • Then execute it:
perl mysqltuner.pl

The script would run multiple checks against your MySQL instance, all checks done by MySQLTuner are documented here.

Also as stated in the official documentation, it is still extremely important for you to fully understand each change you make to a MySQL database server. If you don’t understand portions of the script’s output, or if you don’t understand the recommendations, you should consult a knowledgeable DBA or system administrator that you trust.

As a good practice make sure to always test your changes on staging environments before implementing them on your production database.

On the same note, if you want to have a worry-free MySQL hosting and focus on your application, I would recommend trying out the DigitalOcean Managed Databases:

https://www.digitalocean.com/products/managed-databases-mysql/

This was mini tutorial was posted from @bobbyiliev in this question in our community: https://www.digitalocean.com/community/questions/how-to-tweak-mysql-mariadb-configuration-for-increased-performance-and-stability

Hope that this helps! Regards, Alex

I always build 512MB SWAP file and is enough to run Apache + MariaDB + WordPress. I run three WordPress blogs into same droplet (512 MB RAM).

I don’t know what DO guys installed into the default WordPress image, but i suggest you to install byourself Apache + MariaDB + WordPress. You can find several tutorial and comentation into the DO community.

For this unexpected crashes i use one bash script that runs with cron every 10 min and check that some services are up (if they are down it restar them). Perhaps it helps you in the future, you can find it here

Try DigitalOcean for free

Click below to sign up and get $200 of credit to try our products over 60 days!

Sign up

Get our biweekly newsletter

Sign up for Infrastructure as a Newsletter.

Hollie's Hub for Good

Working on improving health and education, reducing inequality, and spurring economic growth? We'd like to help.

Become a contributor

Get paid to write technical tutorials and select a tech-focused charity to receive a matching donation.

Welcome to the developer cloud

DigitalOcean makes it simple to launch in the cloud and scale up as you grow — whether you're running one virtual machine or ten thousand.

Learn more
DigitalOcean Cloud Control Panel