MTBF = 0.1593625498 hours while MTTR
= 9 seconds (0.002500000 hours) (total mean time for server reload after fault detection):
Mean time to repair (MTTR
) is the membership function of the fuzzy evaluation "excellent", "good", "general" and "poor", as shown in Figure 6:
The scaling-up of the mean time to repair MTTR
occurs during the augmenter of the unconditional probability of the failure in software components (Figure 10).
However, in some cases performance improvement decreases with an increase in MTTR
. During analysis, more improvement has been observed in flow time based objective function in comparison to tardiness based objective function
of JS is 3P and the MTTR
of EJS is 4P in the symmetric model, where P is the smallest prime number greater than N.
We evaluated the HS-GRSP scheme in terms of four performance criteria, including TTR (ATTR and MTTR
), effect of PU appearance, fairness of channel utilization, and degree of overlapping.
Thus the busy time between two successive failures (which is inter-breakdown time) is assumed to follow a Gamma distribution with [alpha] = 0.7 and [beta] = MTTR
x e / (1 - e) x 0.7 and the duration of each breakdown (which is also known as repair time) is also assumed to follow a Gamma distribution with [alpha] = 1.4 and [beta] = MTTR
In the worst case scenario while only one common channel is available and CRs can meet only once on the common channel, MTTR
= n (other less extreme cases are discussed in Section 6.3).
is a basic measure of the maintainability of repairable items, it represents the average time required to repair a failed component or device.
MTBF of Outages Examples Availability Number outages Failure rate MTBF MTTR
per year (failure/hour) (years) (hours) 0.99999 315 3.60E-02 0.0032 0.00028 0.99999 1 1.14E-04 1.0 0.0883 0.99999 0.05 5.71E-06 20 1.77 Availability Reliability (1 year) 0.99999 0% 0.99999 36.78% 0.99999 95.12% "Reliability is the "probability of success" for a given period of time.
For example, Virtela sets an aggressive 4-hour global guarantee for Mean Time to Restore (MTTR
) and bested this by more than half in 2011, averaging just 1.48 hours.
where, MTTF is the mean time to failure and MTTR
is the mean time to repair for components and the machine.