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Cc: freebsd-hackers@freebsd.org
Subject: Re: dump reads more than restore writes?
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> Is dump reading substantially more than restore is writing?

Quite possibly, esp. if the source disk is nowhere near full and/or
most of the files being handled are small.  dump reads every inode
on the disk, including those which are unallocated, and probably
reads entire data blocks -- or even entire FS blocks -- even when
only part of the block contains useful data.  Restore writes only
what it has to.