Re: [LUG] CENTOS webservers Load Balance

good notes indeed Simon, sounds as though you have plenty of experience in provisioning, thats valuable.Â

Have you found any particular VPS providers to be good?

What Layer 7 ,Application networking is it you reference like a software proxy setup ?

Thinking of factoring a rapid expansion from a single VPS to many and wondered if there are any good tips for Linux boxes to balance them and or script a provisioning to locate the least used resource for the next website creation.Â

I'd like to know what limits are around Apache on a processors and memory how many sites can it run before creaking ?

On Mon, Mar 2, 2015 at 5:18 PM, Simon Waters <simon@xxxxxxxxxxxxxx> wrote:

On 2015-03-02 14:50, Matt Stevenson wrote:

I'm interested in anyones experience of transitioning from dedicated Servers to Linux Virtual Servers what Load Balance either at the switch or Application level?

Most of what I've done has load balanced using multiple reverse proxy caches, these days it makes more sense to push that layer to a CDN, who'll keep 99% of the rubbish out of your way for less than it will cost you to provision one virtual squid box with decent bandwidth, and provide bandwidth cheaper than you can buy it elsewhere. They'll also be faster.

You can also provision fairly meaty virtual machines with the usual virtual machine providers, and these providers also provide high performance database engines for common purposes.

So you have to get pretty big to even need to think of load balancing, unless it is purely for availability or manageability. Thinks thousands of concurrent users on most web applications, which puts you quite high up the chain in terms of user base.

As such I've mostly managed to avoid virtual load balancing, but at a push I'd probably use the virtual server providers tools, because they'll fail over between bits of their cloud better than anything I'm likely to set-up.

Switches don't really exist at this level, so nearly all the load balancing is layer 7, based on proxies and cookies or source address. These proxies are often application agnostic, at the pain of logging in again if the specific host your session is with dies mid session. The only application level changes I've seen are to put session information into shared storage, to avoid that repeated login. See also what the CDN providers offer.

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