gbde: ufs & ffs

[Poul-Henning Kamp]

In message <200411231239.33577.list-freebsd-2004 at morbius.sent.com>, RW writes:
>
>Why does the gbde section of the Handbook recommend running fsck -p -t ffs, 
>which calls  fsck_ffs, when ordinary filesystems are checked with fsck_ufs.

ufs and ffs are two sides of the same one filesystem.  The difference
is mainly that ufs _could_ potentially be shared with another filesystem
using a different storage policy as well.

Therefore, in my opinion, the correct name is FFS.

>According to 
><http://sixshooter.v6.thrupoint.net/jeroen/faq.html#UFS-DIFF-FFS>, ffs runs 
>on top of ufs "providing directory structure information, and a variety of 
>disk access optimizations".

That is 180 degrees wrong.

>Am I correct in thinking that soft-updates 
>protect ffs from inconsistency, so that only a background ufs check is 
>required?

yes.

>Is it possible to background check gbde partitions? If so, can it be done 
>after booting is complete?

yes.
-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.