On 10/27/2013 08:44 PM, Myklebust, Trond wrote:
On Oct 27, 2013, at 8:27 PM, Christoph Anton Mitterer <calestyo@xxxxxxxxxxxx> wrote:
On Mon, 2013-10-28 at 00:17 +0000, Myklebust, Trond wrote:
...and if the checksums are any good, then all you need to do to
substitute a database is to realise that a good data checksum is
invariant under renames.
Don't quite see what you mean...
Sure the checksums stay the same, but consider you have many millions of
files, and you moved them around and thus the paths in the DB are
incorrect... verifying the files will become very much a pain in the
a**, especially when multiple files don't verify anymore.
Or what if you have many small similar files, where errors could lead to
a checksum that was a correct one for another file,... when the paths
are no longer valid you cannot know if this was a correct file or not.
If you have lots of small files, and you really do need to associate them uniquely with the checksum, then try something like:
ln <filename> /path/to/database/<SHA512 identifier>.<inode number>
Hard links and inode numbers are also generally invariant under 'mv'.
Trond--
Then you end up with large directories and an extra name per inode that needs to
be stored and extra lookups for each file when you do a whole file system crawl.
Certainly not as easy as adding and xattrs with that information :)
Ric
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