[DRBD-user] tuning DRBD

Ben bench at silentmedia.com
Tue Jun 12 21:17:52 CEST 2007

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

On Jun 12, 2007, at 11:34 AM, Lars Ellenberg wrote:

> whether or not the tcp buffer fills up or not does not change things.
> in this case the tcp buffer does only what it was supposed to do,
> smooth the tcp stuff. having a larger buffer (which, depending on your
> actual network performance may never fill up) cannot possibly increase
> latency?

Doh. Of course. Thanks for point out the obvious to me. :)

>>>> 3. What's a reasonable formula for determining max-buffers? Does
>>>> increasing them imply I should increase something else too?
> if you tune it too small, io will throttle on it.
> to not thottle here, it should be larger than the maximum expected
> amount of in-flight io (io requests submitted but not yet completed).

I see. I don't suppose there happens to be a way to see what my in- 
flight io high/average watermark currently is?

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