Edward Henigin ed@datafoundry.net writes:

I'm surprised noone has pointed this out yet, but there is no problem. All you are monitoring off of this are deltas. If at time T the counter is -30000, and at time T' it's -29000,

 -29000

• -30000

======== 1000

So ops/sec are 1000 / (T' - T)

The deltas work just fine, regardless of whether the counter happens to be positive or negative.

Except for rollovers. "interesting" things happen when the counter rolls from (approx) 2^31-1 to -2^31.. My mrtg-graphs have these wonderful spikes every few days bacause of this (yes, I can fix this, as well. I just don't have the time right now).