Benefits of Virtual Private Servers: VPS vs Shared Web Hosting
A web page posted » here (titled » What is VPS Hosting?) claims that Shared web hosting providers cram as many as 500 customers onto a single server (« i.e. slumlords of the webhosting world), while countering that VPS providers limit the number "at most" to 20.
While I feel this is an exaggeration (for marketing purposes), you get the gist » many accounts are assigned to each Shared web hosting server, while relatively few get assigned to Virtual Private Servers.
For you & me (where web hosting is concerned) less is more. For example, our old web host (Lunarpages) limited our use of server resources (on their Shared web hosting account) to a measly 1% .. for both memory & CPU.
This suggests Lunarpages puts at least 100 customers on each Shared web server. I say "at least" cuz few sites will max-out and use the whole 1%, the entire time (24x7 .. given that 100 accounts per server x 1% of server resources allowed per account would = 100% of the server's resources).
Realize too, that a single high-traffic site can overload a web server faster than 500 low-traffic sites. So there's more to consider than simply comparing the number of accounts assigned to each physical server.
But in general, less accounts are better .. for you & me, that is — not for our web hosting provider, who (being in business to make a buck) seeks to maximize revenue by maximizing the number of account$ assigned to each physical server. (It's simple math.)
Nevertheless, dedicated resources can definitely help prevent one busy site from overloading the entire server .. tho it's still possible, particularly when your server experiences what's known as » excessive disk Input/Output ..
..
which occurs when visitors to one (or more) of the sites hosted on your particular hardware node (i.e. » the physical server) begin requesting files (that are not currently stored in memory) faster than your server's disk-storage system can retrieve them.
The queue (for these requested files) then starts backing up. In other words, you start WAITING for your pages to load in your browser. Waiting suks.
As you probably know, hard disks work much more slowly than RAM/memory. Memory is ~ 1,000 times faster. It's performance is measured in micro-seconds. Compare that with hard drives, whose performance is typically measured in milli-seconds.
Big difference between milli and micro (1,000X), especially when you multiply it by all the files requested that a storage system on a particular server has to locate (seek, access) and send (transfer).
Hard drives can therefore be overloaded more easily than either memory (RAM) or your CPU. When overloaded (as previously mentioned), disk-storage systems are unable to keep up with requests for files.
Consequently, your site becomes unresponsive. Your visitors quickly lose patience. Some of these visitors will leave for greener pastures .. where they won't have to wait. (You've likely experienced this yourself.) The result » you lose traffic. So you can see how excessive disk I/O can be an administrator's worst enemy.
Might be worth noting here .. that your web hosting provider gets paid whether your site is responsive or sluggish. I don't know a single person who has ever received a refund due to an unresponsive web server.
Web hosting providers only lo$e if you decide to move to another host. And things have to get pretty bad for you to do that. (Cuz moving your site is such a hassle.) My point is » you tend to care more about your server's responsiveness than does your web host. (Because it affects you more directly.)
Terminology Note: with a Virtuozzo-based Virtual Private Server, tech support geeks sometimes refers to your individual VPS as a 'container,' or a 'virtual environment,' while the physical server upon which your VPS runs (the actual box where your files are stored) is sometimes referred to as the 'hardware node.' So you can see how use of the generic term 'server' can be confusing.
And this doesn't take into account use of the term 'server' as it applies to software web servers such as Apache. Usually (but not always) the term 'web' preceding 'server' implies software.
In later pages, I'll address in greater detail the factors affecting VPS responsiveness, such as » Server Load, CPU latency, and Disk Input/Output (which is typically the biggest bottleneck in virtualization today).
Unfortunately, some of these metrics are available only to our web hosting provider. This can make it difficult (for you and me) to troubleshoot site responsiveness problems .. which can be frustrating, especially if the techs at your web host (like those at most web hosts) are experts in the art of assigning blame elsewhere.
After we acquire (and configure) all the cool features we want, our VPS boils down to one thing » ensuring maximum responsiveness, which is typically the time it takes a web page to load (in a browser) after a visitor clicks a link to a page on your site.
So we'll definitely address those factors in detail. But we're getting ahead of ourselves. First, let's nail down the basics of VPS web hosting.
On the next page, I'll begin with the end, and share the decision I ultimately made, regarding the selection of a good VPS web hosting provider.
Readers with time-constraints should find this page helpful. Tho I caution you against blindly following my lead, as things in the world of web hosting can change quickly. (Today's web hosting studs can become tomorrow's nags.) Heck, by the time you read this, I might've moved on to another web host. So I urge you to be a good capitalist and do your own research.