Re: cannot mount small FFS filesystem?

["Jonathan A. Kollasch" <jakllsch%kollasch.net@localhost>]

On Mon, Jun 14, 2010 at 03:48:15PM +0200, Hubert Feyrer wrote:
> 
> I have a storage device that only has 47k space. I'd like to put FFS
> (v1 or v2) with journaling on it. newfs(8) works fine, but mount(8)
> complains:
> 
>       mount_ffs: /dev/vnd0a on /mnt: incorrect super block
> 
> The commands I give for testing:
> 
> # dd if=/dev/zero of=img bs=512 count=94
> # vnconfig vnd0 img
> # newfs -m 0 -O 1 /dev/rvnd0a
> # mount -o log /dev/vnd0a /mnt
> 
> Full log with output is appended below.
> 
> I've tried adding -m0 and -O1 to newfs, but couldn't mount it,
> without without logging.
> Is there anything obvious I'm missing?
> 
> Thanks a lot in advance!
> 

Seems to work in rump_ffs for me, without WAPBL.

Lowest size I can seem to get WAPBL working easily on is .5MiB.

newfs -Z -F -o space -m 0 -s 1024 /tmp/disk.ffs
(tunefs has been modified to not attempt to read a nonexistent SB)
tunefs -l 64k /tmp/disk.ffs 
rump_ffs -o log /tmp/disk.ffs /mnt

Also, where did you get a media with only 94 sectors?

        Jonathan Kollasch