[DRBD-user] MySQL-over-DRBD Performance

Art Age Software artagesw at gmail.com
Wed Dec 19 20:40:14 CET 2007

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

> > Hmmm, it looks to me like non-drbd is **faster** than
> > drbd-disconnected from my numbers, which I would expect. Am I
> > mis-reading?
> what I meant is that they are close, and that I have seen on various
> setup either the exact same values, or one or the other showing less
> latency. yes, obviously in _your_ setup, non-drbd apears to have less
> latency, as is naively expected anyways. but I wanted to point out that
> there sometimes you also see the counter-intuitive thing, namely
> disconnected drbd showing less latency than the underlying device by
> itself. which is where said "funny effects" come into play.

Got it. Thanks for the clarification.

> > The 2 nodes are identical - right down to the io subsystem (identical
> > RAID-10 hardware with battery-backed write-back cache enabled and
> > identical model hard drives).
> did you _measure_ that.
> or do you just "know" that.

Well, I ran the MySQL benchmarks **without** DRBD on both machines and
got similar results. However, I will re-run the dd tests in the other
direction and report back the results.


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