Slowdown issues...

Started by Vekseid, December 09, 2008, 12:01:33 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Vekseid

...were caused by someone else hogging the system : /

Please contact me -immediately- if this happens again, it takes ~10 minutes for my host to resolve.

I may end up holding out a tin cup again, if this happens often, to get a real server or something. Though I've been told that if this happens again I can contact them to deal with the abusive client more harshly.

In any case, needed tables have been converted to innodb, which should stop some of the slowdowns, and the issue with the greedy nodebuddy has been resolved. I'm still planning on smf 2.0 and I may custom compile php to further slim down the server.

Since I originally suspected a DOS attack, mod-evasive has been enabled. This might tell you to slow down if you click refresh too fast. If needed I will up the limits - just contact me at vekseid@elliquiy.com

Sorry about that everyone, thank you for your patience.

Vekseid

Gah, if anyone wants me to explain any of that, just reply and ask, right now Vekseid=tired.

King_Furby


Algibard Glirings

Maybe it's because of DDoS attack filter but after database conversion Elliquiy became slower for me - some pages load, but browser shows that it's still loading, others end up with "Failed to connect" error message. If it's something to do with DDoS filter limits, then please, up them a little. If something else, will have to wait till it's fixed.
(Failed to connect happens when trying to open even one page at a time)

Greenthorn

I would like you to explain please.
 

Vekseid

Should clarify...

If something besides pms are slower. They were not meant for what you people have done with them : /

Will explain in a bit

MagicalPen

*Is also lost/confused as to what Vek is talking about. Sits down front row for further explanation*

My On and Offs
When the Ink Runs Dry

Looking/Available for New Games

King_Furby

I am always confused about all this tec stuff, but it is interesting to read for some reason.


Trieste

The way I understand it, Elliquiy is not on its own server. It shares server space with other sites, which can be any type of site including another forum.

Servers come in different sizes, and have finite amounts of resources as well as bandwidth. Basically, Elliquiy just moved from (as I understand it) a small server to a medium server ... think of it like your packrat roommate.

If you have an apartment and you have six roommates and you all have allocated parts of the apartment, it's going to get a little bit bad for everyone else if one roommate collects rocks. Rocks of all sorts. And that roommate gets more rocks and more rocks, until their rock collection has grown too large for the apartment and they start infringing on your space, and storing rocks in your bed. You are going to get cranky, and you're also not going to be functioning very well, because there are rocks in your bed and you can't sleep very well, now can you?

Essentially, one of the other sites hosted on E's server was collecting rocks and hogging space... so E couldn't function as well as it should have been able to. The lag, I think, could have been due to the other site having too many visitors or putting out too much content, therefore taking up too much of their allocated bandwidth ... or it could have been them having too many processes and taking up much of the RAM/virtual memory/whatever of the server. (Kind of like if you play the Sims on a system not meant to handle it ... it'll stutter.)

That's my take on it and hopefully I explained it well. Veks is free to let me know if I am incorrect.

Vekseid

Actually...

You can think of Elliquiy as having its own flat in a very expensive condo complex. It is on what is called a 'virtual private server', which is like having your own server, but you actually share certain critical resources with others, just as how in an apartment complex you share resources, but have your own bed, kitchen, etc. And can generally do what you want, but if you play the music too loud there's going to be a problem.

Previously, Elliquiy was on a shared host - basically like sharing a house with about two dozen others, and we were the biggest.

World Enough and Time, In the Dark and other forums that you usually find are often on massively resold hosts - you share a mansion with hundreds of individuals.

Eventually, Elliquiy is going to need its own house - a dedicated server. It might be possible for me to skip to a mansion from the vps, or even multiple homes or mansions (heh). Depending on if I can optimize things okay - there is a lot more I can still do and I can still purchase a bigger complex in the condo, here.

It just takes time. Right now... we have a situation where Elliquiy is doing something that SMF was never, is not, and probably never will be designed to cope with - four hundred thousand private messages, so pms are probably going to be the most frustrating bit.

Vekseid

Anyway, I explained innodb in the other topic. Hopefully that's sufficient.

Mod-evasive is an extension to our webserver software that attempts to stop a single individual from bringing down the server. Essentially, it tracks how often a person makes requests, and if they do so too often in too short a time, the server just drops them instead.

The current settings are fairly permissive - it would only take a few people to 'shut Elliquiy down' if they really knew what they were doing. However, it lets me see who those few would be much easier, and then I can just drop their connections before they even start talking to the server.

And perhaps persue legal action, if I find out who they are.

Mod-evasive doesn't take up a significant amount of resources, however. I just wanted it because I don't want to scramble in response to a DOS attack like a chicken with my head cut off : /




Custom compiling php - php is currently using a sort of 'default' setup, not tuned specifically for Elliquiy's needs or this server's capabilities. Since php execution (basically what actually runs the dynamic portions of the site - accepting and parsing this post, displaying it to you, etc) takes up most of our usage of the processor, it can allow for some significant performance gains to be so tuned.

Hope that helped?

King_Furby


Trieste

Denial of Service attack. I think it's essentially when you fling so much information at the server that it cannot process it all and starts to slow down, then shut down.

DDOS is the same thing, I think, but on a larger scale.

Algibard Glirings

Quote from: Trieste on December 09, 2008, 04:21:23 PM
Denial of Service attack. I think it's essentially when you fling so much information at the server that it cannot process it all and starts to slow down, then shut down.

DDOS is the same thing, I think, but on a larger scale.

DDoS stands for Distributed Denial of Service, meaning the attacker has remote machines under control which can run DoS software. Usualy it's PC's all over the globe that are infected with Trojans. That means that if "hacker" knows what he's doing, you might never find out the real source of the attack.

Vekseid

Denial of Service (DOS) is basically an attack that tries to get the target service to stop functioning for real individuals. There are many different types and to be honest I have only in the past few months begun to look at seriously hardening Elliquiy against such things.

A Distributed DOS (DDOS) is the same thing, but using multiple machines, usually something sinister like a Botnet but can be used in reference to something genuine but ow like getting us linked on Digg.

As Mr. Glirings notes, most famous DDOS attempts are via botnets. However, making that traffic look genuine requires a lot of machines, and doing it with only a few can let the defender just pick the attackers off one by one. The largest botnet DDOS I've seen on a site Elliquiy's size didn't even involve over a hundred machines, usually it's about a dozen.

Vekseid

And yeah, there's a giant buffer issue I didn't properly configure, so I need to fix that and hopefully things will go smoothly again.