[linux-lvm] Strange dm-cache activity at startup

[Joe Thornber]

On Thu, Sep 10, 2015 at 11:30:27AM +0200, Stefan Ring wrote:
> Is this normal/expected? What does it do? Why does it write back huge
> amounts of data to the HDD after each system start?

No, this is not expected.  The most likely cause is your system was
not shutdown cleanly so dm-cache has no choice but to assume all
blocks are dirty and need writing back.  Make sure your volumes are
being deactivated as part of shutdown.

- Joe