On 01/29/2016 11:40 PM, Tejun Heo wrote:
Hello,
To implement meaningful IO resource accounting and distribution, it's
necessary to know how much each IO or a group of IOs costs. With
rotational devices, due to the inherent low performance and
concurrency, direct IO cost estimation could be replaced with
provisioning time slices - whatever compositions of IOs which can be
performed in the same amount time are of the same cost. However, this
approach can no longer be used for modern non-rotational
high-performance devices with high level of concurrency.
It'd be great to talk about the problem, how to work around the
problem in the near future, and what solutions can be employed in the
long term.
+1.
Very good point. We have similar issues with asymmetric multipathing
across different transports.
Cheers
Hannes
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