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Web Hosting - Redundancy and Failover
Among the more useful innovations in computing, actually invented decades ago, are the twin ideas of redundancy and failover. These fancy words name very common sense concepts. When one computer (or part) fails, switch to another. Doing that seamlessly and quickly versus slowly with disruption defines one difference between good hosting and bad.
Network redundancy is the most widely used example. The Internet is just that, an inter-connected set of networks. Between and within networks are paths that make possible page requests, file transfers and data movement from one spot (called a 'node') to the next. If you have two or more paths between a user's computer and the server, one becoming unavailable is not much of a problem. Closing one street is not so bad, if you can drive down another just as easily.
Of course, there's the catch: 'just as easily'. When one path fails, the total load (the amount of data requested and by how many within what time frame) doesn't change. Now the same number of 'cars' are using fewer 'roads'. That can lead to traffic jams.
A very different, but related, phenomenon occurs when there suddenly become more 'cars', as happens in a massively widespread virus attack, for example. Then, a large number of useless and destructive programs are running around flooding the network. Making the situation worse, at a certain point, parts of the networks may shut down to prevent further spread, producing more 'cars' on now-fewer 'roads'.
A related form of redundancy and failover can be carried out with servers, which are in essence the 'end-nodes' of a network path.
Servers can fail because of a hard drive failure, motherboard overheating, memory malfunction, operating system bug, web server software overload or any of a hundred other causes. Whatever the cause, when two or more servers are configured so that another can take up the slack from one that's failed, that is redundancy.
That is more difficult to achieve than network redundancy, but it is still very common. Not as common as it should be, since many times a failed server is just re-booted or replaced or repaired with another piece of hardware. But, more sophisticated web hosting companies will have such redundancy in place.
And that's one lesson for anyone considering which web hosting company may offer superior service over another (similarly priced) company. Look at which company can offer competent assistance when things fail, as they always do sooner or later.
One company may have a habit of simply re-booting. Others may have redundant disk arrays. Hardware containing multiple disk drives to which the server has access allows for one or more drives to fail without bringing the system down. The failed drive is replaced and no one but the administrator is even aware there was a problem.
Still other companies may have still more sophisticated systems in place. Failover servers that take up the load of a crashed computer, without the end-user seeing anything are possible. In fact, in better installations, they're the norm. When they're in place, the user has at most only to refresh his or her browser and, bingo, everything is fine.
The more a web site owner knows about redundancy and failover, the better he or she can understand why things go wrong, and what options are available when they do. That knowledge can lead to better choices for a better web site experience.
Bring These Important Tips to the Table in a Telecommuting Argument Are you tired of the sound of the alarm clock every morning? Are you equally tired of trying to figure out what to wear every day (ladies) and fighting the rush hour traffic to get to the office in time? How about spending almost your entire paycheck on gas to put in your car to get you to work? There is a way around all of this of course – telecommuting. When you telecommute to work, you can catch a little bit of extra shut eye and head to work in your pajamas, without even getting in the shower. But aside from the convenience factor, there can be a lot of other good reasons why telecommuting makes sense. If you can put together a convincing enough argument for your employer, you may find yourself going to work in your bedroom slippers before you know it. The first thing you have to keep in mind about your telecommuting argument is that you have to make sure you have plenty of evidence that telecommuting will be beneficial to your employer, not just you. Sure, you would love to be able to see the kids off to school in the morning and take your coffee break in front of your favorite soap operas, but your boss doesn’t care about all of that. Though you don’t have to hide the fact that telecommuting will obviously have its privileges for you from your boss, remember to include plenty of ammunition for benefits to the company as well. What can you bring to the table in terms of telecommuting advantages for your boss? Point your boss to a growing amount of research on the internet that shows that big companies have seen big increases in productivity when they started letting people telecommute and work from the comfort of their homes. Everyone knows that a rested and stress free employee is a productive one, and offices can be filled with more distractions than your home (gossiping employees, phones always ringing). Some companies have seen increases in productivity of over 50%, something that is sure to get your boss’s attention. You can also point out to your boss that absenteeism takes a nosedive when people telecommute. No need to take a fake sick day to get out of going to office when you work from home, and even when people are under the weather, when the office is in the next room, they still tend to get a few things done on a day that would have been a total write off otherwise. Another selling point for your boss may be that everyone else is already doing it. More than half of the companies in the US have employees that telecommute, with great results. Your boss won’t want to let the company fall behind – and your boss will know that offering what other companies have is important for employee retention. Make sure your boss knows that what you are asking for is not out of the ordinary in any way. Beyond the selling points for your boss, you can be specific about a few benefits to you. Bosses know that gas is major issue for employees – telecommuting is a way they can let you cut back on that big expense, without feeling under pressure to respond with wage hikes. If you have customers that live near your house, let your boss know it will be easier to meet them face-to-face if you work from home. Last but not least, let your boss know that you believe you can deliver more to the company from the comfort of your home - more work for the same pay is always music to an employer’s ears. Web Hosting - Sharing A Server – Things To Think About You can often get a substantial discount off web hosting fees by sharing a server with other sites. Or, you may have multiple sites of your own on the same system. But, just as sharing a house can have benefits and drawbacks, so too with a server. The first consideration is availability. Shared servers get re-booted more often than stand alone systems. That can happen for multiple reasons. Another site's software may produce a problem or make a change that requires a re-boot. While that's less common on Unix-based systems than on Windows, it still happens. Be prepared for more scheduled and unplanned outages when you share a server. Load is the next, and more obvious, issue. A single pickup truck can only haul so much weight. If the truck is already half-loaded with someone else's rocks, it will not haul yours as easily. Most websites are fairly static. A reader hits a page, then spends some time skimming it before loading another. During that time, the server has capacity to satisfy other requests without affecting you. All the shared resources - CPU, memory, disks, network and other components - can easily handle multiple users (up to a point). But all servers have inherent capacity limitations. The component that processes software instructions (the CPU) can only do so much. Most large servers will have more than one (some as many as 16), but there are still limits to what they can do. The more requests they receive, the busier they are. At a certain point, your software request (such as accessing a website page) has to wait a bit. Memory on a server functions in a similar way. It's a shared resource on the server and there is only so much of it. As it gets used up, the system lets one process use some, then another, in turn. But sharing that resource causes delays. The more requests there are, the longer the delays. You may experience that as waiting for a page to appear in the browser or a file to download. Bottlenecks can appear in other places outside, but connected to, the server itself. Network components get shared among multiple users along with everything else. And, as with those others, the more requests there are (and the longer they tie them up) the longer the delays you notice. The only way to get an objective look at whether a server and the connected network have enough capacity is to measure and test. All systems are capable of reporting how much of what is being used. Most can compile that information into some form of statistical report. Reviewing that data allows for a rational assessment of how much capacity is being used and how much is still available. It also allows a knowledgeable person to make projections of how much more sharing is possible with what level of impact. Request that information and, if necessary, get help in interpreting it. Then you can make a cost-benefit decision based on fact. |