[linux-lvm] Filesystem corruption with LVM's pvmove onto a PV with a larger physical block size

[Stuart D. Gathman]

On Fri, 1 Mar 2019, Cesare Leonardi wrote:

> I've done the test suggested by Stuart and it seems to contradict this.
> I have pvmoved data from a 512/512 (logical/physical) disk to a newly added 
> 512/4096 disk but I had no data corruption. Unfortunately I haven't any 
> native 4k disk to repeat the same test.

Use a loopback device with logical block size set to 4096 to confirm
that your test does detect corruption (using the same LV, filesystem,
data).

I believe by "physical sector", the original reporter means logical,
as he was using an encrypted block device that was virtual - there
was no "physical" sector size.  It was "physical" as far as the
file system was concerned - where "physical" means "the next layer
down".

Indeed, even the rotating disk drives make the physical sector size
invisible except to performance tests.  SSD drives have a "sector" size
of 128k or 256k - the erase block, and performance improves when aligned
to that.

-- 
 	      Stuart D. Gathman <stuart at gathman.org>
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.