Talk:Myth of the nines

message: delivering its service to the user 99.999% of the time it is needed.
No, no?  I believe that 99.999% is a measure of the absolute number of minutes (or whatever) in a year; the phrasing we're using now isn't accurate for systems which must be usable as much as possible when the business is *not* in operation 24/7/365.25.  --Baylink 18:13, 11 July 2006 (UTC)
thread_title:  What it means 

message: I've heard someone say that contracts specifying nines of uptime typically exclude counting periods of "planned downtime", which could in fact extend into hours or days or longer as long as the outage is planned and scheduled.  In such contracts, only "unplanned downtime" is usually considered to count against the alloted downtime. Can anyone else confirm this convention and maybe integrate into the article if this is indeed a common industry interpretation? -- Bovineone 20:59, 13 August 2006 (UTC)
thread_title:  Planned vs Unplanned downtime 

message: I think a reference to the costs of a [Network outage] would be interesting. However, that article is currently in such a bad state that i do not want to add it here. And i do not have the necessary information to extend it. Dbu 13:50, 22 January 2007 (UTC)
thread_title:  Costs 

message: The calculation of the uptime as a percentage is widely used in  SLAs so the article is providing some useful information. 
I would like to add that there is no technical reason for it to be all nines. The expression of "five nines uptime" may be popular but you could express the uptime as 99.8% or 99.98% or whatever, albeit with less geek appeal.
Anyway, under the section entitled  The myth explained the writer is confusing the technical issues with the business issues. There is nothing misleading or controversial about guaranteeing your uptime as a percentage and stating the remedies for failing to meet the guarantee. The collateral damage caused by downtime should be well understood by the customer, but the topic for such discussions should be "risk management", not uptime calculations.
As a service provider, it is not up to me to measure the impact that a system failure will have on individual customers. They are responsible for measuring that impact on their own businesses. I offer a percentage of uptime for a given price. They then decide if my guarantee is acceptable. If it is not, I can offer a higher percentage at a higher price. The guarantee is only one side of the equation, though. The other side is the remedies to the customer if I fail to meet the terms of my uptime guarantee. This should also be covered in the SLA.
I think the article should be renamed, removing the reference to "myth" and that subsection reworked, perhaps into something that examines the uses of uptime percentages in business risk management.
Further, I would like to see the article expanded to include more info concerning probability calculations. For example, I know that a single server with no redundancy will have a downtime of no less than 2 hours if the hard disk fails. (The presumption is that 2 hours is about how long it will take to replace the disk and restore from backups) But what's the probability that it will fail more than once a year? Or how do I calculate the uptime probability if I use use two servers in a cluster? Or three? That is the kind of information that I came to this article looking for but didn't find.
Stephen Brown 13:03, 20 April 2007 (UTC)
thread_title:  There is nothing "mythical" about the nines 

message: The article states: "For example, a system of ten components (eg. disks, motherboard, PSU, RAM, mains-power, network...), each with 99.999% availability, only has 99.99% overall availability (ie. one tenth as good)."  This seems to be wrong.  99.99 isn't one tenth of 99.999.  It's only one-thousandth less than 99.999. -18:23, 22 August 2007 (UTC)
replies: text: Subtract the percentages from 100% and you'll get it. 0.0001% is ten times less (failures) than 0.001% — so ten times better. -- intgr #%@! 21:15, 22 August 2007 (UTC)
replies: text:  The fact is, that the overall availability is not equal to “one tenth” of something, the calculation uses tenth power (the resulting availability is 0.9999910), but the result is almost the same (~99.9900004+), because (1 - \varepsilon)^n \approx 1 - n\varepsilon for small \varepsilon. --Mormegil 11:44, 26 October 2007 (UTC)
thread_title: One tenth as good

message: I'm not convinced this is a myth. There are no references to back up the claim that "The myth of the nines is the implicit assumption that if the computer is operating 0.99999 of the time, then the user's business is operating 0.99999 of the time."
I notice the page Five nines redirects to this article. I would much rather have the content of this article moved to that page, and include explanatory notes about the implications or "false assumptions" about five nines. The encyclopedia is supposed to be factual and having an article about a supposed myth instead of spelling out the facts is not appropriate. Barrylb (talk) 09:22, 15 July 2008 (UTC)
replies: text: I am thinking of redirecting Five nines and similar articles to High availability which seems to cover the facts of the nines. Whether it is a myth can be dealt with separately here. Barrylb (talk) 09:26, 15 July 2008 (UTC)
thread_title:  The Myth 

message: I propose that the following sentence be reworded.
After an outage, the humans using the computer have to scramble to catch up, perhaps apologising to customers, calling them back, entering data written on paper during the outage, and other unfamiliar chores.
If we are going to refer to ourselves in this manner, aren't we just asking for the computers to begin the usurpation? GuamIsGood (talk) 02:54, 14 October 2008 (UTC)
thread_title:  On the "Matrix". 

message: I have removed the WikiProject tag, as this article is either a redirect or deleted. If you oppose, please restore the tag. Thank you, fahadsadah (talk,contribs) 15:52, 30 March 2009 (UTC)
thread_title:  Wikiproject Computing