Michael,

michael schuster schrieb:
Roland Rambau wrote:
gang,

actually a simpler version of that idea would be a "zcp":

if I just cp a file, I know that all blocks of the new file
will be duplicates; so the cp could take full advantage for
the dedup without a need to check/read/write anz actual data

I think they call it 'ln' ;-) and that even works on ufs.

quite similar but with a critical difference:

with hard links any modifications through either link are
seen by both links, since it stays a single file (note that
editors like vi do an implicit cp, they do NOT update the
original file )

That "zcp" ( actually it should be just a feature of 'cp' )
would be blockwise copy-on-write. It would have exactly
the same semantics as cp but just avoid any data movement,
since we can easily predict what the effect of a cp followed
by a dedup should be.

  -- Roland




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