[CentOS] Load balancing...

[Sean Hart]

On 3/3/11 3:51 PM, aurfalien at gmail.com wrote:
> On Mar 3, 2011, at 3:43 PM, Todd wrote:
>
>> Hi All,
>>
>> Can anyone help me hash out how best to load balance a website that  
>> is getting considerable traffic?  In the past I only have experience  
>> with BigIP where you have a load balancing device that keeps track  
>> and send traffic to the best server possible at the time. This was a  
>> proprietary system that I think was something Dell rebranded.
>>
>> Right now, the whole site is is 400gb of video, HTML5, Apache, PHP,  
>> MySQL, runs on a single box with 16gb of RAM and mirrored /var/www/ 
>> html (2x1tb raid level drives). I have a Comcast 50/10 connection, 5  
>> statics and I am seeing about 125 unique visitors a day. The site  
>> runs fine, but in anticipation of more traffic as well as a learning  
>> experience I would like to load balance.
>>
>> Obviously I need a second server just like the one it is running on  
>> now. I will probably spec something out that is capable of 32gb of  
>> RAM.
>>
>> What about a dedicated load balancing device? What specs should this  
>> be? How much RAM, HD, processor? It is sufficient to buy something  
>> with a GB NIC and say 4gb of RAM? Can one go slower but more RAM,  
>> small HD?  I don't really quite know how intensive a task this  
>> decision making process is for the load balancer..
>>
>> Right now, as example, I have an Untangle Firewall and it runs on a  
>> old AMD with 2gb RAM, GB NIC and it seems to do just fine.
>>
>> My local computer store has several P4 2.8ghz with 2GB of RAM for  
>> like $99....
>>
>> Can anyone enlighten me on specs, proper setup, caveats....?
> Well a bit outside what I know which isn't much, but...
>
> What about external DNS provider with round robin DNS?
>
> Or if you have control over your DNS, then you can easily do round  
> robin.
>
> Qucik and ez faq on round robin;
>
> http://www.zytrax.com/books/dns/ch9/rr.html
>
> Hope this helps.
>
> I do this for my mail servers.
>
> - aurf
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Hello,

Building a high throughput, highly available site is a tough job, and
there's a reason good sysadmins get paid what they do.  But to give you
some direction on Load Balancers.

BigIP (Made by f5) is the hands down leader of the Load Balancer world. 
You will pay dearly for it (20K each, min), but depending on your needs,
may very well be the best choice for you.
http://www.google.com/url?sa=t&source=web&cd=1&sqi=2&ved=0CCgQFjAA&url=http%3A%2F%2Fwww.zeus.com%2Fdocuments%2Fen%2FGa%2FGartner_Inc._Magic_Quadrant_for_Application_Delivery_Controllers_24.09.09.pdf&rct=j&q=load%20balancer%20gartner%20magic%20quadrant&ei=zipwTdeQG5TCsAOe1N3CCw&usg=AFQjCNGeL_a0Jpco1EVVObiAS0mWSnbbqg&cad=rja

Zeus also makes a decent product, made to run as software.  The software
will run you ~9K I think, but is pretty feature rich.  Requires hardware
to go with it. http://www.zeus.com/products/load-balancer/

IPVS or LVS can work as a really simple/free solution:
http://www.linuxvirtualserver.org/software/ipvs.html

Round robin DNS would balance load, but will cause problems if one of
them goes down.
You could also set up apache or squid to do proxying...

Cheers,
Sean