[dm-devel] DM-Cache Writeback & Direct IO?
Joe Thornber
thornber at redhat.com
Wed Jul 8 14:48:29 UTC 2015
On Wed, Jul 08, 2015 at 11:03:42AM +0200, Christoph Nelles wrote:
> Hi,
>
> Can the dm-cache writeback cache buffer direct IO or goes direct IO
> always immediately to the origin device?
Yes, the device mapper layer knows nothing about direct IO vs page
cache IO.
> I am currently performing tests and see that random direct write IO
> never hits the cache, even after overwriting the same region over
> and over.
Could you try with the latest kernels and the new smq policy please?
- Joe
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