On Fri, 15 Oct 2004 03:19, Arnt Karlsen <[EMAIL PROTECTED]> wrote: > > Increasing the number of machines increases the probability of one > > machine failing for any given time period. Also it makes it more > > difficult to debug problems as you can't always be certain of which > > machine was involved. > > ..very true, even for aero engines. The reason the airlines like > 2, 3 or even 4 rather than one jet.
You seem to have entirely misunderstood what I wrote. Having four engines on a jet rather than two or three should not be expected to give any increase in reliability. Having two instead of one (and having two fuel tanks etc) does provide a significant benefit. However the needs of an aircraft are significantly different from a mail server. When a mail server has a problem we have the option of pulling the plug and then taking some time to fix it. There is no equivalent operation for an aircraft. When installing two engines in an air-craft that can run on a single engine you are trading off an increased risk of having an engine fail against a greatly decreased risk that an engine failure will kill everyone on board. With mail servers if you have a second server you have more work to maintain it, more general failures, and you have no chance of saving anyone's life to compensate. Finally consider that one of the main causes of server unreliability is mistakes made during system maintenance. Increase the amount of work involved in running the systems and you increase the chance of problems. -- http://www.coker.com.au/selinux/ My NSA Security Enhanced Linux packages http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark http://www.coker.com.au/postal/ Postal SMTP/POP benchmark http://www.coker.com.au/~russell/ My home page -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
