On Wed, Dec 07, 2005 at 05:31:24PM +0900, MASUDA Hideo wrote:
> Hi, all.
> 
> # uname -a
> NetBSD xenu 3.99.13 NetBSD 3.99.13 (DSM_XENU) #1: Wed Dec 7 16:59:56 JST 2005
> h-masuda@dsmserv.dsm.cis.kit.ac.jp:/usr/current/src/sys/arch/i386/compile/DSM_XENU i386
> # mount -t mfs -o -s=10240,-p=755 none /.var
> # mount -t union /.var /var
> 
>  Using mfs is OK, but,
> 
> # mount -t tmpfs -o -m=755 none /.var
> # mount -t union /.var /var
> mount_union: /.var on /var: Operation not supported

The underlying FS must support whiteouts, which tmpfs probably does not.

Jaromir
-- 
Jaromir Dolecek <jdolecek@NetBSD.org>            http://www.NetBSD.cz/
-=- We can walk our road together if our goals are all the same;     -=-
-=- We can run alone and free if we pursue a different aim.          -=-