linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* 'Subset' Hard Links
@ 2009-09-18  0:02 Micah Dombrowski
  2009-09-18  1:31 ` Sunil Mushran
  0 siblings, 1 reply; 3+ messages in thread
From: Micah Dombrowski @ 2009-09-18  0:02 UTC (permalink / raw)
  To: linux-fsdevel

Hello,

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?

Thanks,
Micah Dombrowski
Department of Physics and Astronomy
Dartmouth College

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2009-09-18  4:26 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-09-18  0:02 'Subset' Hard Links Micah Dombrowski
2009-09-18  1:31 ` Sunil Mushran
2009-09-18  4:26   ` Sage Weil

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).