[linux-lvm] Backup superblock for thin provision?

Gionatan Danti g.danti at assyoma.it
Tue May 17 13:22:29 UTC 2016

> There is always the option to take 'metadata' snapshot and just
> thin_dump content of metadata to a file (located in some 'safe' place)

Something as "dmsetup reserve_metadata_snap", thin_dump, "dmsetup 
release_metadata_snap" ? If so, I'm already using for testing purpose ;)

> However validation of 'restore'  if there are some 'snapshots' is
> questionable as the b-tree describing mapped blocks may change
> significantly
> so 'rescued' content may than reference lots of bad blocks.

Sure, with snapshots the situation is surely more complex, as due to the 
CoW the old metadata can point to stale data, right?
> If you want to just protect 'superblock' against disk fault - usage
> of 'raid' could be an option - but ATM there are some 'related' costs
> with management of 'stacked' device tree.

Both my tmeta and tdata reside on a RAID6 array provided by a 
BBU-protected RAID card, so I should be safe here.

Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti at assyoma.it - info at assyoma.it
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