Clustering Solutions and Zero Downtime Hosting Pitfalls

Written by Godfrey Heron

Title: Clustering Solutions and Zero Downtime Hosting Pitfalls Author: Godfrey Heron Email: Word Count:1452 Copyright: © 2005 by Godfrey Heron Article

Publishing Guidelines: You may publish this article in your newsletter, on your web site, or in your print publication provided you includerepparttar resource box atrepparttar 134338 end. Notification would be appreciated but is not required. -------------------------

Clustering Solutions and Zero Downtime Hosting Pitfalls

There are a number of benchmarks, which we may use to evaluate hosting companies. One of these is, reliability.

Like most things in this life, reliability in web hosting is typically a function of how much we are willing to spend for it. In essence, a “cost-effectiveness” equation needs to be determined and solved.

Reliability can be measured in terms of percentage availability. Industry personnel will talk of reliability in terms of system availability with three (99.9%), four (99.99%) or five nines.(99.999%).

Typically, web-hosting availability exceeding three nines wasrepparttar 134339 purvue of extremely large companies with multiple layers of redundancy built into their network and software systems. However technology has now brought high-availability theory and cost-effective reality into alignment.

High availability can be achieved by removing, as far as possible, any “single point/s of failure”, or, where this is not altogether possible, minimizingrepparttar 134340 time spent in a “failure” situation.

One ofrepparttar 134341 ways in which small businesses and ISP’s can reasonably avoid single point of failures is by employing server farm clustering and load-balancing solutions.

Webopedia defines server farm clustering as follows:

“A server farm is a group of networked servers that are housed in one location. A server farm streamlines internal processes by distributingrepparttar 134342 workload betweenrepparttar 134343 individual components ofrepparttar 134344 farm and expedites computing processes by harnessingrepparttar 134345 power of multiple servers.

The farms rely on load-balancing software that accomplishes such tasks as tracking demand for processing power from different machines, prioritizingrepparttar 134346 tasks and scheduling and rescheduling them depending on priority and demand that users put on repparttar 134347 network. When one server inrepparttar 134348 farm fails, another can step in as a backup.”

It is important to note, that typically, web servers, which are load-balanced in such a manner, display one external IP address torepparttar 134349 public Internet, while using internal network IP’s to communicate between repparttar 134350 clustered servers and load balancer. Now this is indeed fantastic! Not only do you receive web site peak demand scalability with web server clusters, but you also haverepparttar 134351 built-in “high uptime availability” component which is so important.

However this is only half ofrepparttar 134352 picture. There are very important cautionary notes to keep in mind.

Where web hosting is concerned, availability depends on two things:

1.Hardware reliability (RAID drives, server clustering etc) withinrepparttar 134353 Data Center;

2.High Bandwidth Internet Connectivity torepparttar 134354 Data Center / Network Operating Center (NOC).

Now, with all your well thought out server clustering solutions, what would berepparttar 134355 result, if, (as had recently occurred in a very high profile web company), a fire inrepparttar 134356 Network vicinity had causedrepparttar 134357 entire Data Center to shut down power for hours. Or, a bandwidth provider torepparttar 134358 NOC had router problems. All your websites would be showingrepparttar 134359 dreaded “Page Cannot be Displayed” page.

The ideal solution therefore would be to employ clustering solutions with servers in entirely different Data Centers with different bandwidth providers. Redundant Data Centers eliminaterepparttar 134360 NOC itself being a single point of failure. This scenario becomes interesting at this point, because repparttar 134361 difficulty of addressingrepparttar 134362 potential problems now increase exponentially.

We now have to deal with DNS caching,repparttar 134363 concept of failover, and how static and dynamic web applications respond to failure events.

Failover and Load balancing are frequently used interchangeably, however they are in fact quite different.

·Load Balancing refers to physically sharing servers capacity, so that one server is not overloaded and swamped with requests.

·Failover however, isrepparttar 134364 process that manually or automatically switches a failed server or bandwidth provider to a standby server or network ifrepparttar 134365 primary system fails or is temporarily shut down for servicing.

As such, failover software is an important function of mission-critical systems that rely on constant accessibility.

Web Hosting: 4 Factors in Choosing a Hosting Company

Written by Richard Martin

When choosing a web hosting company there are a whole lot of different factors that should go into your decision making process. One ofrepparttar biggest factors should be:

1) Phone support. Email support is nice, but email occasionally falls in betweenrepparttar 134337 virtual cracks. Getting someone onrepparttar 134338 phone when your site goes down can take a lot of mystery out ofrepparttar 134339 entire process. A lot ofrepparttar 134340 bigger web hosting companies offer toll free support and weekend hours to boot. Phone support is a great benefit for any web hosting client.

2)Another factor to use in deciding whether to use a particular web hosting company is their history. How long has this company been in business? Web hosting companies that have been in existence for less than a year might not berepparttar 134341 best choice. A hosting company with a proven track record and a ton of happy clients is certainly a good sign and might work well for you.

3)How aboutrepparttar 134342 company's software? This varies widely between web hosting companies. I am rather fond of Cpanel merely because I am used to it, understand whererepparttar 134343 buttons are and whatrepparttar 134344 features do. It's much easier to stick with something you know than switching to a new User Interface. Some web hosts offer Frontpage features and others don't. Another specific area you might want to research arerepparttar 134345 statistics programs. What sort of web statistics software is included with your web hosting account? Is Awstats included? This is one area you definitely want to heavily research before signing up.

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