Micah Dombrowski wrote:
I couldn't think of anywhere else to ask such a question, and google
is useless as I have no unique keywords. I am wondering if it is
possible with some/any filesystems to have multiple hard links to a
file, some of which only point to a subset of the file's data.
Eg:
firstname -> all data bytes 1 to 10
secondname -> bytes 3 to 10
thirdname -> bytes 5 to 7
This would clearly require some interesting locking of the file WRT
writes, but it seems like it should be possible, and even easy for
read-only access. I deal with moderately large data files (50+GB),
and such a thing would be incredibly useful to me for pulling out
interesting bits of my data without having to make copies of the data
itself.
A related method I was wishing existed would allow concatenation of
files simply by deleting all but one hard link, and changing the
remaining one to point to all of the original files' data as
fragments. This would be great, as 'cat'ing together six 10GB files
is pretty slow, and it seems silly to be copying all of that data
around when I only need one actual instance of the full data on disk,
and that instance already exists, albeit in a fragmented manner.
Do any tools for doing this sort of thing exist?
btrfs should able to handle most of this.
http://git.kernel.org/?p=linux/kernel/git/mason/btrfs-unstable.git;a=commitdiff;h=c5c9cd4d1b827fe545ed2a945e91e3a6909f3886
However, note that file systems operate in terms of blocks. So the start
offset
would need to be block aligned.
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