Re: ext2 file sizes

Clem Taylor (clemtaylor@home.com)
Thu, 16 Sep 1999 02:33:44 -0400


"Richard B. Johnson" wrote:
> On Wed, 15 Sep 1999, Blankenship, Keith wrote:
> > I am having some difficulty with the ext2 file systems. I need to generate a
> > file that will be > 5 Gigabytes, and there appears to be a file size cap at
> > approximately 2 Gig. I am running what appears to be a version 2.0.36
> > Kernel. Is there anything I can adjust, or do to increase the maximum file
> > size? Or is there a newer kernel that may work?
>
> Note that on a 32-bit machine, toff_t, used as fpos_t, for file offsets,
> i.e., lseek, is unsigned 32 bits. You will not be able to access such a
> file on a 32-bit machine. There has been some work on changing this
> to 'long long' (__kernel_loff_t, in ../asm/posix_types.h although you may
> need a new 'C' runtime library to take advantage of this.
>
> What on earth are you doing with a single _file_ of that size? If you
> need a gob of storage for data acquisition, you might be better off
> with a dedicated raw device. Since you access it in blocks, rather than
> bytes, you won't have a size limitation for a few more years.

I work with compressed video and my average file size is 3-6 gigs,
increasing
all the time (higher bitrates). A while back I looked into using Linux for
a
video application and gave up and went with Solaris and Irix because of
the lack
of large file support. I was hoping that 2.4 would have large file support
(and
not just on 64 bit platforms), but that isn't looking promising based on
comments here. Going to a 64 bit off_t (on 32 bit platforms) is a major
change
and will have a serious impact in user space. Just look at all the pain
Solaris
and Irix had in making the move.

--Clem

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