In a Q&A forum, the response to a question concerning failure rate and repair times for a redundant system demonstrated yet another person confusing MTBF with something it is not.
The responder to the question mentioned that the reference to repair time implied the need for MTBF as a metric. Then went on to describe MTBF as the duration of repair time, which should not change given a redundant system over a non-redundant system.
Here’s a snippet:
“repair time” hints to MTBF while “failure rate” relates to statistical failure, not typically related to “end of life”.
So please do not mix up these two things.
This is a new way of confusing MTBF for me.
Sure, we often associate MTBF with repairable systems and MTTF with non-repairable systems. We regularly also use MTTR, mean time to repair, for repair times.
Isn’t the way we estimate MTBF by inverting the failure rate? I didn’t know that confusing MTBF and failure rate was possible. Nor did I know that failure rate isn’t related to end of life.
I suspect the confusion stems from the MTBF association with repairable systems and not being clear on the difference between MTBF and MTTR. At first, I thought it was a typo, yet the responder made the incorrect reference a few times.
Have you seen this one before? Any other ways out there to that people are confusing MTBF? Let me know. Let’s build a pantheon of MTBF confusion methods.
Back From a Month Off
For the regular readers of this blog, first, thanks! Second, I’m back, or trying to be back. This past month has been busy, and while I needed the extra time to focus on the move to a new home, I missed writing. I also really miss the ongoing conversations, Q&A, comments, etc that occur here. [Note: we’re not happily approaching our 10th year in the new home – and I really do need to start writing more often – you can help by sending over short articles suitable for the NoMTBF series.]
So, I’m back. The plan is to get back into the rhythm of weekly articles. Plus, I’m looking for ways to add ebooks and courses to the site. Let me know what works for you or what you would like to have available here. – cheers, Fred
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