[squid-users] AUFS vs. DISKS

[Amos Jeffries]

On 16/07/2015 3:37 a.m., Marcus Kool wrote:
> 
> I think that changing the baseline to 8K is not required since the queue
> congestion
> warning is normally seen only a few times, so the baseline value of 8 is
> doubled
> only a few times.
> A new baseline value of 256 (5 doublings) makes sense to me since most
> disks have
> a hardware queue depth of 256.
> For those systems where many disks are tortured with I/O the doubling
> will appear
> a few (log2(#disks)) times.

Good point. It is an arbitrary initial length.

Fred and Fred;

 Could you guys who have been seeing these warnings logged please
present a grep of those cache.log lines so I can get a better handle on
how many doublings your queues are actually requiring ?

I count 5 and 6 warnings respectively in FredB's two earlier log traces.
So 8*(2^6)=512 entries with an extra x2 normal I/O thread count making
it about 1K queue entries required minimum.

Cheers
Amos