Re: file size limits?

On Sat, Jul 29, 2000 at 12:03:32PM -0400, Andreas Schiffler wrote:
> Date: Sat, 29 Jul 2000 12:03:32 -0400
> From: Andreas Schiffler <aschiffler@home.com>
> X-Mailer: Mozilla 4.73 [en] (X11; U; Linux 2.2.16 i686)
> To: linux@slg.org
> Subject: Re: file size limits?
>
>
> Scott,
>
> the file size limit has two roots. One is the filesystem itself and
> one is the libC support for large files.

Don't forget the third -- and probably most important root: the Linux VFS
layer.
    
> The new glibc 2.0 and 2.1 have added support for 64bit filepointers as
> it was designed to run also on 64bit CPUs. The relevant functions
> fseek, fstat have corresponing function with a "64" attached -
> fseek64, fstat64, etc. Programs (i.e cat ) that want to use large
> files have to be compiled using these functions rather than the
> standard 32bit functions. The new glibc 2.1 probably default all file
> operations to 64bit internally and figure out if a filesystem can
> support it on the fly, so that one does not need to recompile. (Does
> anybody know if this is true?) In any case you'll need a system that
> is build on the latest glibc.
>
> Now the ext2 filesystem (unpatched) has a 2G limit:
> [1]http://e2fsprogs.sourceforge.net/ext2intro.html

No, it doesn't. It will happily deal with >2GB files on 64 bit platforms
like the Alpha and the UltraSPARC. The limiting factor on 32 bit systems is
the VFS layer, which only supports 32 bit file pointers. This limitation
will apply to any filesystem which goes through the VFS layer.

> You could try XFS with full 64bit support:
> [2]http://oss.sgi.com/projects/xfs/
>
> ReiserFS says that they will support 64bit soon (see Status page):
> [3]http://devlinux.com/projects/reiserfs/
>
> And JFS looks promising with a 2.2.16 kenel patch available and full
> 64bit support:
> [4]http://oss.software.ibm.com/developer/opensource/jfs/
>
> I you get anything working, please report back to the mailing list.
> I'd be very interested in seeing this working on my own system, but
> don't have the time to test it out myself.

I'm running kernel 2.4.0-test5 here, which supposedly has the 32 bit
limitation in the VFS removed. Can't test it, though, because I don't have
2GB of free space on either of my hard drives. :(

That said, I will probably switch to XFS when it becomes available, although
for other reasons than long file support.

-- 
  -Sean Connor  (sec@konatsu.dhs.org)
                (sec@cableregina.com)
                (sec@softhome.net)
The fact that an opinion has been widely held is no evidence that it
is not utterly absurd; indeed, in view of the silliness of the
majority of mankind, a widespread belief is more often likely to be
foolish than sensible.
--
Saskatoon Linux Group Mailing List.
--
To unsubscribe, send mail to
'linux-request@slg.org' with
'unsubscribe' in the body.