If you are just starting your website and don’t receive very much traffic, then shared hosting is the ideal solution. However, if your website’s audience is consistently growing, you’ll want to consider upgrading. You don’t want to run the risk of your website running slowly or, even worse, your server crashing because it can’t handle the traffic. If you anticipate an increase in visitors, do yourself a favor and switch to VPS.
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With VPS Hosting, there are multiple instances of separate operating systems on a machine—thus giving you your own virtual private server. So while you still may be sharing a physical server at the data center, with your own virtual operating system, you’re able to have dedicated resources such as RAM, bandwidth, and disk space. In other words, the environment mimics having a dedicated server—at a lower cost!
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Essentially, here’s the criteria I would use to judge things – if your site is made up of primarily static, HTML-based content, then you probably don’t need a VPS package.  However, if you have a large amount of files stored, multiple sites, dynamic content, and the possibility of major traffic from time to time, then you might consider upgrading to a VPS. It’s a powerful package that allows you to do more than you could with a shared hosting plan, but requires less investment than a dedicated server.

• RAID-10 Disk Configuration for VPS Hosting
Shared hosting is like you are living in a room with a lot of friends. It means you must fit in the same room and you must split the cost of several things because it is affordable and cheap. However, several individuals are sharing the same space, it means everyone needs to live within a space with restricted resources among them. You will have to use the same things (that sounds a little unhygienic).
A virtual private server (VPS) is a virtual machine (something like a computer divided into many smaller machines using special software).[1] They are often used by Internet hosting providers. Multiple VPS's run on the same machine, but they are separated as they will only share hardware resources without interfering on software level. A VPS is dedicated to the customer's needs, has the privacy of a separate physical computer, and can run server software. There are many platforms that can run a VPS. Some of them are VMWare and Xen.[2]

Website owners with misconfigured CMS scripts or out of date security versions of code risk MySQL injections particularly that can lead to the theft of an entire database. VPS admin login panels, cPanel logins, FTP connection routes, and email servers running on Apache are all common attack vectors for script bots which are programmed to target common URL structures on domains.
Shared hosting is not meant for websites that use large amounts of RAM. As your website grows and you add more and more content, you will start to see a decrease in your website’s load times. As soon as this happens, it’s an indication that you are maxing out your limits. Upgrading to a VPS will enable you to scale your website without having to worry about slow load times.
The main problem faced by users paying for VPS through bitcoin is the fact that while payments to VPS service providers are generally monthly, bitcoin generally does not support recurring payments. This is mainly due to the fact that bitcoin is a push technology i.e. a transaction which has to be initiated by the publisher rather than the client or the receiver.

The web hosting company will also provide regular web server software, installed programming language extensions, & firewall upgrades. Managed VPS plans running Windows normally include the use of Plesk for administration of domains and web server settings, while VPS plans running Ubuntu, Debian, Slackware, etc. can be administered using Webmin or Virtualmin under a free open source license.
In answering this question, maybe it’s better to examine how VPS hosting fits in to the overall offerings of most hosting companies. Shared hosting is just that – your site is hosted on a machine with a bunch of other sites, and each of you share the same resources, including RAM, disk space, and CPU.  Your site uses what it needs if it’s available, and if it’s not – well, that’s the limitation of shared hosting. Likewise, a dedicated server is also self-explanatory –  your site is the only one hosted on server, and you have all the aforementioned resources available at your beck and call. Dedicated hosting is therefore  for those large sites with big databases and lots of traffic, whereas the limitations of shared hosting’s usually prevent it from housing that kind of site. Dedicated servers are also relatively expensive, while one can get a shared hosting plan for under $10 per month.