[linux-lvm] df reporting incorrect size?

[Theo Van Dinter]

On Mon, Jul 08, 2002 at 04:59:17PM -0400, Ben Snyder wrote:
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/spheravg/spheralv
>                              59G   20k   56G   0% /test
> 
> 
> WTF?!?!  Where'd that 3G go?  Does LVM mess with things so that the OS 
> cant read volumes correctly?  Or is there another issue that I might be 
> running into?

This isn't a LVM question, it's a filesystem question....  Specifically:

$ man mke2fs
...
       -m reserved-blocks-percentage
              Specify the percentage of the filesystem blocks reserved for the super-user.
              This value defaults to 5%.
...

So 5% of 59GB is ~3GB.  59-3 = 56GB available.

As you can tell, 5% is huge.  For non-root/OS filesystems, I almost
always set that to 0.  Look at tune2fs to see how to do that without
recreating the FS.

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