Many thanks for all the feedback.

The idea works for those applications that supports snapshots.
Like Sybase / SAP Adaptive Server Enterprise, Sybase / SAP IQ Server, DB2, MongoDB, MariaDB/MySQL, PostgreSQL etc..

Anyhow, back to the origin question:
Is there a way how to re-create the cow- format.
so that lvconvert --merge can be used.
Or by having lvconvert --merge to accept to read from a "cow file"

If that would be possible, than instant recovery would be possible from an external source, like a backup server.

Regards Tomas

Den ons 23 okt. 2019 kl 08:58 skrev Gionatan Danti <g.danti@assyoma.it>:
Il 23-10-2019 00:53 Stuart D. Gathman ha scritto:
> If you can find all the leaf nodes belonging to the root (in my btree
> database they are marked with the root id and can be found by
> sequential
> scan of the volume), then reconstructing the btree data is
> straightforward - even in place.
>
> I remember realizing this was the only way to recover a major
> customer's
> data - and had the utility written, tested, and applied in a 36 hour
> programming marathon (which I hope to never repeat).  If this hasn't
> occured to thin pool programmers, I am happy to flesh out the
> procedure.
> Having such a utility available as a last resort would ratchet up the
> reliability of thin pools.

Very interesting. Can I ask you what product/database you recovered?

Anyway, giving similar ability to thin Vols would be awesome.

Thanks.

--
Danti Gionatan
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Assyoma S.r.l. - www.assyoma.it
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