Cannot write file larger than 2TB on x86_64?

[Justin Piszcz <jpiszcz@lucidpixels.com>]

The kernel is 2.6.9-42.ELsmp on RHEL4 x86_64.

servername$ dd if=/dev/zero of=4.8tb_file bs=1M count=4800000
File size limit exceeded
servername$ (stopped at 2TB)

The 64bit should not need the option obviously, because it is 64bit, is this a b
ug in the kernel?

For 32bit:
.config - Linux Kernel v2.6.22 Configuration
  ..............................................................................
   ..................... Support for Large Single Files ......................
   . CONFIG_LSF:                                                             .
   .                                                                         .
   . Say Y here if you want to be able to handle very large files (bigger    .
   . than 2TB), otherwise say N.                                             .
   .                                                                         .
   . If unsure, say Y.                                                       .
   .

For 64bit:
.config - Linux Kernel v2.6.22 Configuration
  ..............................................................................
   ............................... Block layer ...............................
   .  Arrow keys navigate the menu.  <Enter> selects submenus --->.          .
   .  Highlighted letters are hotkeys.  Pressing <Y> includes, <N> excludes, .
   .  <M> modularizes features.  Press <Esc><Esc> to exit, <?> for Help, </> .
   .  for Search.  Legend: [*] built-in  [ ] excluded  <M> module  < >       .
   . ....................................................................... .
   . .    --- Enable the block layer                                       . .
   . .    [ ]   Support for tracing block io actions                       . .
   . .          IO Schedulers  --->                                        . .
   . .
                                 .