Arch Linux

uberscientist

Member

Registered: 2012-01-27

Posts: 84

Why my ram usage went to zero on my VPS during a traffic spike?

Hi, I've been running a Arch x86_64 VPS for a few months and had my first traffic spike that seemed to cause some issues.
I don't really have any way of getting feedback from users (yet) but I imagine there was probably some service issues.

Here's a screenshot from the control panel:

I didn't get a screenshot at a higher resolution, but it was actually a few up and downs going from 0-400mb instantly.

I'm running NGINX for the static server which is probably what was taking most of the brunt.

Anyone have an idea as to what happened? Or what log files I could check? The nginx error.log is just full of favicon 404 requests

Lynden

Member

Registered: 2011-11-10

Posts: 23

Re: Why my ram usage went to zero on my VPS during a traffic spike?

nginx (de/re)spawns it's childs every so often depending on your configuration, maybe that's causing the 0<>400MB spikes. Honestly I have no idea.

I do have one helpful suggestion. Adding the following to your config, it does wonders in shutting those favicon 404 errors up.

location /favicon.ico {
    empty_gif;
}

uberscientist

Member

Registered: 2012-01-27

Posts: 84

Re: Why my ram usage went to zero on my VPS during a traffic spike?

Thanks Lynden, I'll add that to my config.

litemotiv

Forum Fellow

Registered: 2008-08-01

Posts: 5,026

Re: Why my ram usage went to zero on my VPS during a traffic spike?

What i personally do is just turn off all logging for static files:

location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
        log_not_found off;
}

About your issue, it could be that both your ram and swap maxed out during the spike. When that happens a whole bunch of processes may get dropped/reset to free up memory, after which it starts to build up again. However, since your drop is so acute and the build-up is not lineair, it may very well be just a monitoring glitch.

Last edited by litemotiv (2012-12-18 11:02:35)

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