Hi Gionatan, 

The system with the issue is with  writeback cache mode enabled. 

Best regards, 

Ryan 

On Mon, 25 Jun 2018, 18:19 Gionatan Danti, <g.danti@assyoma.it> wrote:
Il 24-06-2018 21:18 Ryan Launchbury ha scritto:
> In testing, forcibly removing the cache, via editing the LVM config
> file has caused extensive XFS filesystem corruption, even when backing
> up the metadata first and restoring after the cache device is missing.
> Any advice on how to safely uncache the volume would be massively
> appreciated.

It is my understanding that a writethrough cache should *never* have any
data that are not on the backing volumes already.
In other words, forcibly removing a writethough cache (ie: disconnetting
the physical cache device) should not cause any harms to
filesystem/data.

Can you show the output of "dmsetup table"?
Thanks.

--
Danti Gionatan
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