Am Mi., 17. März 2021 um 03:59 Uhr schrieb Chris Murphy
> On Tue, Mar 16, 2021 at 7:39 PM Qu Wenruo <> wrote:
> > > Using that restore I was able to restore approx. 7 TB of the
> > > originally stored 22 TB under that directory.
> > > Unfortunately nearly all the files are damaged. Small text files are
> > > still OK. But every larger binary file is useless.
> > > Is there any possibility to fix the filesystem in a way, that I get
> > > the data less damaged?
> >
> >  From the result, it looks like the on-disk data get (partially) wiped out.
> > I doubt if it's just simple controller failure, but more likely
> > something not really reaching disk or something more weird.
> Hey Qu, thanks for the reply.
> So it's not clear until further downthread that it's bcache in
> writeback mode with an SSD that failed. And I've probably
> underestimated the significance of how much data (in this case both
> Btrfs metadata and user data) and for how long it can stay *only* on
> the SSD with this policy.

Sorry Chris. I might have expressed this wrongly. But the
btrfs-filesystem was never on bcache. On bcache was a xfs-filesystem
that I backed up (rsynced) to the btrfs-filesystem when everything
went wrong. And I quickly gave up hope for that xfs afterwards, due to
the (lost) cached data of the directory-structure. That's why I'm
focusing on getting the backup on the btrfs-filesystem back.
But the possibility that some data is really wiped out or as Qu said,
that something is not reaching the disk gives me a direction to
investigate further. Maybe the raid-enclosure or the FC got damaged (I
ruled that out in the beginning). Eventually a failed raid-rebuild or
so. That would explain why so much data is missing.
Thank you.


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