ITIL INTERVIEW - PART 9

1     Service Design Availability,  Reliability.

Reliability define service run without interruption

MTBSI (Mean Time between Service Incidents)

MTBSI = Available time in hours /Number of breaks.

MTBF = Total downtime in hours /Number of breaks

2     Service Design Availability Maintainability.

How fast service can be restore after failure.

MTRS Mean time to restore service.   

MTRS =Total downtime in hours /Number of service breaks

3     Explain below Availability Terms?

Continuous Availability: design the service to get 100 % availability. This

Service has no unplanned or plan downtime.

Fault Tolerance No interruption in service after the component fail.

4     Calculate Availability /reliability/reliability /maintainability for below  situation

Service is running  7 days * 8 hours and down  running for    2910 hours  with 3 breaks  of  3 ,1 and 6 hours .

Calculate   Reliability (MTBSI)  =   2910 /3 = 970 hours.

Calculate   Reliability ( MTBF ) =   2910 – ( 3+1+6 ) /3  =   870 hours.

Calculate Availability     = 2910 –( 3+1+6) / 2910 *100  =99.65 %.

 Maintainability = (1+6+3) = 10 hours.