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

[Stefan Ring]

On Fri, Sep 11, 2015 at 2:51 PM, Joe Thornber <thornber at redhat.com> wrote:
> 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.

I would have hoped that the distro scripts would take care of this.
Apparently not, for whatever reason :(. I have since upgraded to
kernel 4.2, and the behavior has not changed. I'll try to reboot today
instead of shutdown and see if anything changes.