Hi,

I disagree, seeing this pattern first hand in resulting large penalty payment on one case (inability to prove that monitoring reported up on certain time when it wasn't responsive). If there's a need to monitor availability, there must be recorded event flow, eg:

Up 11:00
Up 11:05
Up 11:10
Down 11:15
Down 11:20
Up 11:25

And why? If we only record:

Up 11:00 - 11:10
Down 11:15 - 11:20
Up 11:25 - ..

There's a difference. Did the monitoring system report 11:05 or was the monitoring system down 11:05? In many cases a need to prove that system was in certain state in certain times. Especially when there are SLA disagreements. Even more importantly, what happened between 11:10 - 11:15 and 11:20 - 11:25?

The SLA behaviour requires that some system noticed something happening at certain point of time. And if there's issues with system responsibility say at 11:05, there needs to be a event showing that the system really did report up.

   - Micke


On 13.02.2015 14:01, Thomas Heute wrote:

Getting back to availability discussion...

To me availability is a set of periods, not so much "time series" and we should just record change of status (closing the previous event and opening a new one).

    - Server is up from 8:00am to 11:30am
    - Server is down from 11:30am to 11:32am
    - Server is unknown from 11:32am to 12:00pm (an agent running on a machine can tell if a server is up or down, if the agent dies then we don't know if the server is up or down)
    - Server is in erratic state from 12:00pm to 12:30pm (agent reports down every few requests)

We were discussing the best way to represent availability over time in a graph, representation in RHQ [1] is very decent IMO, can be extended with more colors to reflect how often/long the website was down for each "brick" (if the line represent a year with 52 blocks, 1 block can be more or less red depending on how long it was done during the week).

But thinking of it more, availability graph is not that interesting by itself IMO and more interesting in the context of other values.
I attached a mockup of what I meant, a red area is displayed on response time graph, that means that the system is down, obviously there is no response time reported anymore in that period. Earlier there is an erratic area, seems related to higher response time ;) Rest of the time the system is just up and running...

Additionally I would want to see reports of availability:
    - overall availability over a period of time (a day, a month, a year...). "99.99% available in the past month"
    - lists of the down periods with start dates and duration for a particular resource or set of resources (filtering options)

Thoughts ?

[1] http://3.bp.blogspot.com/-0MsmG5h5i5E/TfjTMZlvx3I/AAAAAAAAABU/6PKDs0RlzuI/s1600/ProblemManagement-RHQ.png

Thomas 


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