Semley Station
- Small system resilience
Large companies have an inherent resilience by virtue of the number of employees and computers on their premises. Small businesses and home-office workers do not have such resources. One computer failure in the large company might result in some disruption to the activities of several workers until the IT department resolve the problem: the same computer failure in a small business can stop all money-earning activities for a long period.
It is possible to build resilience into small business systems by identifying the critical applications or computers and making sure that there is an alternative method if a system fails. For example, if one office member takes incoming phone calls and enters the order details into a computer, the information on that computer could be frequently copied to a second computer. In the event of the first computer failing, the second computer has the information to allow normal business to continue while the faulty machine is repaired.
It is of course vital to ensure that each machine has spare capacity if it is likely to be called upon to provide resilience. However, it is often possible to use lower-specification computers where resilience is being planned in a system, and there is little appreciable increase in cost. Two or three cheap P1 or P2 computers can be joined together with a hub, and copies of the data stored on each hard disk.
Windows and Microsoft Office products do work well together when used in such a configuration. One machine can have a tape drive or CD-burner to act as the master backup machine. If that machine should fail, the cd-roms are still readable in the other machines, or the tape drive can be transferred to a working machine to access backed-up data when required, and the disruption to normal office activities is minimised.
Sharing information between machines by publishing it on one machine and viewing it on others is the first step to forming an Intranet, where information is published in the same manner as on the World-wide-web, but using local networks as the connections. Access time is quick, and access methods are by the standard web-browser. PC's running Linux can access Windows files and printers, and make available their own files and printers, using a freely-available system called Samba. Linux has a good reputation for avoiding the problems associated with internet-borne viruses and trojans that have plagued Windows machines around the world, and it makes sense to use a machine running Linux to access the internet on behalf of the remaining machines in the network, although Windows machines should still be protected by a good virus scanner.
In the case of Southwest Scimpart, the web-site acts as a buffer to allow Scimitar owners to search the technical help pages to obtain possible answers to their enquiries, or check on the existence and price of parts. If the web-site is down for any lengthy period, the incoming phone calls increase, and start to prevent sales calls from getting through. Ensuring that a second web-site is always available is a cheap solution. It also allows the load to be shared between the sites so that during normal operation (both sites up and running), loading on the web-sites is unlikely to rise to the point where pages take a long time to load. Similarly, having more than one e-mail account allows communications to continue when an ISP's server fails.
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(C) Information Resource Consultancy Ltd 2004