Preallocated file size...

[Luis Claudio R. Goncalves]

Howdy again!

   I don't belong to the list right now... so if want to reach me,
please reply to my personal address.

> 	Could you clarify slightly?  I would expect
> 	the file to be truncated, at the limit of the
> 	quota (or of the physical disk), but I don't
> 	grok the zero-filled part.

   But this is what occurs when you try to write beyond the
quota. This is a feature called sparse files and this serves to
reduce [useless [zero-filled]] disk usage... And you do have this
feature in Solaris, Linux and probably on other systems.
   The patch sets the right size of the file.
   A friend of mine (Fábio) did a little example on how it works...:

------------------------[ Example 1
olive at thor:~$ dd of=test.sparse seek=10k bs=1
Hi this is a test.
19+0 registros de entrada
19+0 registros de saída
olive at thor:~$ ls -l test.sparse 
-rw-r--r--   1 olive    users       10259 Feb  8 16:25 test.sparse
olive at thor:~$ ls -s test.sparse
   1 test.sparse
olive at thor:~$ du test.sparse
1	test.sparse
olive at thor:~$ exit

------------------------[ Example 2
olive at thor:~$ dd of=test.sparse seek=10k bs=1
Hi, this is another test.
26+0 registros de entrada
26+0 registros de saída
olive at thor:~$ od -a test.sparse
0000000 nul nul nul nul nul nul nul nul nul nul nul nul nul nul nul nul
*
0024000   H   i   ,  sp   t   h   i   s  sp   i   s  sp   a   n   o   t
0024020   h   e   r  sp   t   e   s   t   .  nl
0024032
olive at thor:~$ exit

					Hope this Helps!

[ Luis Claudio R. Goncalves                  lclaudio at conectiva.com.br ]
[ BSc in Computer Science -- MSc coming soon -- Gospel User -- Linuxer ]
[ Fault Tolerance - Real-Time - Distributed Systems - IECLB - IS 40:31 ]
[ LateNite Programmer --  Jesus Is The Solid Rock On Which I Stand  -- ]