Perform action based on load avg

Posted by sfx on Server Fault See other posts from Server Fault or by sfx
Published on 2012-08-30T14:50:53Z Indexed on 2012/08/30 15:39 UTC
Read the original article Hit count: 325

Filed under:

linux

|

ddos

|

high-load

I'm running some web applications on an debian server and have to struggle with ddos attacks sometimes. It's eating up all my resources and I can't ssh anymore into the server. An idea was to drop all connections if the load avg is too high, so there are still resources for me and accept new connections if the load avg is low enough. Since this has to work under heavy load I'm afraid a cronjob wouldn't be fast enough or take too much resources.

tl;dr: Is there a way to configure the behavior if the load avg is above a specific threshold?

© Server Fault or respective owner

Related posts about linux

apt-get install and update fail

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I've got a problem with apt-get update and apt-get install ... commands . every time update or installing fails and errors are : Get:1 http://dl.google.com stable Release.gpg [198B] Ign http://dl.google.com/linux/chrome/deb/ stable/main Translation-en_US Get:2 http://dl… >>> More
kernel module compiling error

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is… >>> More
Build-Essentials installation failing

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I am having trouble accessing the several critical header files that show to be a part of the build process. The "Ubuntu Software Center" shows "Build Essentials" as installed: Next I did the following two commands, which did not improve the problem: ~$ sudo apt-get install build-essential [sudo]… >>> More
Updating Debian kernel

as seen on Super User - Search for 'Super User'
I'm trying to update my Debian machine to 2.6.32-46 (which is the new stable). However, after doing apt-get update my apt-cache search linux-image shows me: linux-headers-2.6.32-5-486 - Header files for Linux 2.6.32-5-486 linux-headers-2.6.32-5-686-bigmem - Header files for Linux 2.6.32-5-686-bigmem linux-headers-2… >>> More
Serial connection over a single USB cable (Windows to linux, or linux to linux)

as seen on Server Fault - Search for 'Server Fault'
I'm helping out with a project for an embedded device that only has USB and no serial. This device is running Linux. These days, when we need to connect to a serial port on a device we typically use a USB to serial adapter (on something like a phone system or a load balancing device, etc). I would… >>> More

Related posts about ddos

How long do DDoS attacks last?

as seen on Server Fault - Search for 'Server Fault'
I realize the answer to this question will vary, which is why I'm asking it. If you've suffered a DDoS attack before - how long did it last? Just trying to get an idea of how long we'll have to continue to wage this battle (going on a couple weeks now). >>> More
DDoS and Heroku

as seen on Server Fault - Search for 'Server Fault'
I use Heroku as my hosting solution. So, if some bad man attacks my site with DDoS, what should I do? >>> More
Brainstorm: Flood/DoS/DDoS Attack prevention ideas.

as seen on Server Fault - Search for 'Server Fault'
This is not a question asking how to stop an attack. This is simply a thread for anyone and everyone to discuss ideas for preventing, dealing with, and keeping your server alive during these attacks. Do not discuss using 3rd party software, this is a place to make your own ideas and read others. Post… >>> More
DDoS and Heroku

as seen on Stack Overflow - Search for 'Stack Overflow'
I use Heroku as my hosting solution. So, if some bad man attacks my site with DDoS, what should I do? >>> More
Anti-DDoS Question

as seen on Server Fault - Search for 'Server Fault'
Our company´s main owner (telecon group) wants us to deploy anti-DDoS mechanisms, such as Arbor Pravail, which is a great idea. Although... I have a question... If our main ISP Backbone provider have no anti-DDoS mechanism, means that there is no point we get the Arbor Pravail? An DDoS attack can… >>> More