[dm-devel] dm: dm-cache fails to write the cache device in writethrough mode

Alasdair G Kergon agk at redhat.com
Sat Mar 23 03:48:03 UTC 2013


On Fri, Mar 22, 2013 at 11:27:16PM -0400, Mike Snitzer wrote:
> So the big difference is the thinp-test-suite uses intermediate linear
> DM layers above the slower sd device (spindle/data) -- whereas in your
> setup the origin device is direct to sd (8:0).
 
I would think the difference is because DM issues (edited) copies of
incoming bios to the layers underneath, so changes don't propagate back
up.

Darrick: if you retest with a dm linear device, does the problem go
away?

Alasdair




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