Re: large_file feature- where is it?

Andreas Dilger
Mon, 09 Jun 2003 23:26:25 -0000

On Jun 09, 2003  14:47 -0400, Darrell Michaud wrote:
> I recently ran into an issue where I couldn't create a file larger than
> 2GB on a particular ext3 filesystem. I was under the (mistaken)
> impression that >2GB support went in before ext3 support, and all ext3
> filesystems would therefore support >2GB files on ia32.
>
> So, I started poking around and found that some of my ext3 filesystems
> have the "large_file" feature flag set on them, and others do
not. I
> cannot find a manpage for mke2fs anywhere that explains how to set this
> flag, either at creation time or afterwards. When I try something like
> "mke2fs -j -O large_file <dev>" mke2fs complains that it
doesn't
> understand the argument. Attempts to create ext3 filesystems using a
> modern debian-based (2.4.18) rescue CD also failed to set the large_file
> flag.
>
> So, I guess my question is, in what version of mke2fs was support for
> large files implemented, and how do you enable it, if it's not the
> default behavior?

That flag is set when a large file is created on the filesystem, and is
not a feature you "activate" per se.  Either your kernel "gets
it" or
it doesn't.

There should never be a problem where you can create a >2GB file on one
filesystem and not on another on the same system with the same program.
Depending if your kernel (unlikely), tool, or libraries, you may still
have problems creating a >2GB, but that isn't the filesystem's fault.

Cheers, Andreas
--
Andreas Dilger