Designing for availability

[asrilrm]

[JoePearson]

[Diarmid]

Boris,

have you considered a Borg collective for support staff?
_________________
"Method goes far to prevent trouble in business: for it makes the task easy, hinders confusion, saves abundance of time, and instructs those that have business depending, both what to do and what to hope."
William Penn 1644-1718

[UKVIKING]

JoePearson

With your example, most NMS tools are set to 5 minutes.... so the multiple bounces w/in may note reacha reporting threshold... but may reach an activity log threshold

When I use to manage NOC we wold see links bounce like a women's beach volleyball game. nice non PC visual

The outages were lesss than 5 minutes so the NMS tool did not report
_________________
John Hardesty
ITSM Manager's Certificate (Red Badge)

Change Management is POWER & CONTROL. /....evil laughter

[JoePearson]

Hmm ... I'm going to design a new network monitoring tool which graphically shows bouncing links as you have suggested. Since I started typing this I've got 70 orders for it.

[BorisBear]

[UKVIKING]

I would rather outsource to Altoids

At least their breath is fresh, unlike the the SD scottsih terriers in book 6

Maybe a new chapter or section is needed

Breath Mints for the SD staff
_________________
John Hardesty
ITSM Manager's Certificate (Red Badge)

Change Management is POWER & CONTROL. /....evil laughter

[asrilrm]

I thought Wookies were much better than androids or altoids whatsoever

[UKVIKING]

Altoids are a a brand name for a Breath mint that is rather strong

Wookies shed too much hair andsome people are allergic t the hair in the NOC
_________________
John Hardesty
ITSM Manager's Certificate (Red Badge)

Change Management is POWER & CONTROL. /....evil laughter

[nasz]

May as well add my own two pennies worth!

Availability of the component is the percentage of time when system is operational. Availability of a hardware/software component can be obtained by the formula given below.

A=MTBF/(MTBF+MTTR)

Example 01:
If we are using equipment which has ‘Mean Time Between Failure’ (MTBF) of 81.5 years and ‘Mean Time To Recovery’ (MTTR) of 1 hour:
MTBF in hours = 81.5*365*24=713940
Availability= MTBF/(MTBF+MDT) = 713940/713941 =99.999859%
Unavailability = 0.000141%
Outage due to equipment in hours per year
Unavailability =0.01235 hours per year.

Whereas, availability of an IS service or system (a combination of hardware/software components) is the percentage of time when the service is operational. Availability of an IS service can be obtained by the formula given below:

A=Uptime/(Uptime +Downtime)

Example 02:
If an IS Service has an agreed uptime of 200 hours for a 30 day period (M-F 0800-1800hrs) and was not available for 3 hours during that time the availability of that IS Service is 98.52% for that period.

200/(200 +3)=0.9852 or 98.52%

However, when an IS Service is utilised by several different business units; and each unit has an individual SLA on place with IS Operations, the following formula can provide a means of calculating the end-user availability of a specific group, region or location, where the IS Service is delivered:

(Agreed Hours* No.of Users-Sum of (incident x Duration* % of users affected))/(Agreed Hours* No.of Users)*100

Example 03:
If an IS Service has an agreed uptime of 200 hours for a 30 day period (M-F 0800-1800hrs) and has a user community of 1000 users in four locations (Each location has 250 users) and one location experiences a single outage of 3 hours. Therefore the end-user availability of that IS Service is 99.625% for that period.

(200 *1000-(3 x 25%) )/(200*1000)*100=99.625 or 99.635%

Availability is typically specified in nines notation. For example ‘3-nines’ availability corresponds to 99.9% availability. A ‘5-nines’ availability corresponds to 99.999% availability.

Availability will be shown in service terms, as opposed to component, system or server terms as the business does not see the component level. All they know is that the email service is unavailable for example. This change in perception of unavailability will help drive IS to be more customer focused.