Data Center Basic, a brief

Today, ICT stand for Information and Communication Technology, for some people specially in big city in the world is basic needs. As we can see, the technology is growth so fast. Internet connection and telecommunication right now is never sleep. Start from my experience on 1995 my first experience browsing using modem 28 kbps, and today my internet connection in my house is 1 mbps, and the contents is vary from text or news become streaming. So that's why the rapid growth of data become exponential growth.
Data center is vital, from data center design, architecture, requirement etc, must be calculate.

A data center or computer centre (also datacenter) is a facility used to house computer systems and associated components, such as telecommunications and storage systems. It generally includes redundant or backup power supplies, redundant data communications connections, environmental controls (e.g., air conditioning, fire suppression) and security devices. 

^{http://en.wikipedia.org/wiki/Data_center} 


Availability, in other word is no downtime, even planed or unplanned downtime.

Availability %	Downtime per year	Downtime per month*	Downtime per week
90% ("one nine")	36.5 days	72 hours	16.8 hours
95%	18.25 days	36 hours	8.4 hours
97%	10.96 days	21.6 hours	5.04 hours
98%	7.30 days	14.4 hours	3.36 hours
99% ("two nines")	3.65 days	7.20 hours	1.68 hours
99.5%	1.83 days	3.60 hours	50.4 minutes
99.8%	17.52 hours	86.23 minutes	20.16 minutes
99.9% ("three nines")	8.76 hours	43.8 minutes	10.1 minutes
99.95%	4.38 hours	21.56 minutes	5.04 minutes
99.99% ("four nines")	52.56 minutes	4.32 minutes	1.01 minutes
99.999% ("five nines")	5.26 minutes	25.9 seconds	6.05 seconds
99.9999% ("six nines")	31.5 seconds	2.59 seconds	0.605 seconds
99.99999% ("seven nines")	3.15 seconds	0.259 seconds	0.0605 seconds

http://en.wikipedia.org/wiki/High_availability


As we can see above, total allowable downtime for planned and unplanned downtime. Base on the SLA/SR
In real life, the cause of downtime can several factors for example blackout power electricity, UPS failure, wrong calcutation, hardware failure, software bugs, human error/unskilled operator.

ICT  especially Enterprise/middle scale must be managed and organize correctly. Strategic, design, transition, operation and continual service improvement should be implement correctly (base on ITIL), YES it's not easy, but it doesn't mean impossible.


The calculation cause by downtime from "IT outage" impact to the lost of revenue.We can calculate base on this equation below.

Quantify Lost Revenue Costs Revenue Cost = (Revenue / Annual Hours) X Impact X Outage Hours Revenue = Gross annual revenue Annual Hours = Total annual business hours Impact = Percentage impact (e.g. % reduction in transactions or dollars during outage) Outage Hours = Number of hours of outage
Quantify Lost Labor Costs Labor Cost = People X Impact X Rate X Hours People = Number of workers affected Impact = Avg. % of work they could not perform Rate = Average employee cost per hour Hours = Number of hours of outage
http://www.firescope.com/QuickStart/Unify/Article.asp?ContentID=15 Well, even I work in mining company it's really different with retail or banking etc,  but I believe that calculation is close to the real cost.