On Tue, Dec 10, 2002 at 10:46:43PM -0800, nate wrote: > John Griffiths said: > > having said that anyone who's todding "five 9's" around as a phrase > > probably wants to do something a bit more demanding. > > either that or they don't know what they are talking about. my > previous company it seemed everything was "critical", but in reality, > it didn't matter if there was on the order of say 20-30 hours a year of > downtime on most servers. I mean, even our most critical servers > were down for more then 2 weeks while they were moved from washington > state to new hampshire on a truck. How many centuries to attempt to > regain 5 9s of uptime after that? :)
I once worked for a company that produced software for telephone systems where the requirement was six nines uptime, that is at most 30 seconds downtime a year. Interesting stuff - at that level you get into having multiple redundant devices constantly sharing all their state which can hot-failover within a couple of seconds. On the telephone system the uptime level is a government requirement, at least in the US. I'm told that Sprint was hauled up before Congress one year for having 90 seconds downtime rather than 30. > the places that I have worked at probably aim for 95% uptime to be > minimum. not sure how many hours or days a year of downtime that > calculates to .. About two-and-a-half weeks. You really don't want to be dropping below that. :) -- Colin Watson [[EMAIL PROTECTED]] -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]