UFS2 and Journaling in 9.1-RC3

[CeDeROM]

On Fri, Dec 7, 2012 at 2:41 PM, Ivan Voras <ivoras at freebsd.org> wrote:
> It looks like you are confusing GEOM journalling (-J) and UFS-SU
> journalling (-j). They are very different, and today you probably want
> to use the latter. If you are installing 9.x from scratch, it will be
> enabled by default. If not, you can use newfs -j or tunefs -j to enable it.

"When any other means fail, read the manual" heh :-)

I am still a bit confused, even after reading [1], because there is no
explanation of difference between GJournal and SU / SU+J (which was
introduced in FreeBSD 9.0). I understand GJournal works below
filesystem level and I dont need to use fsck. SU/SU+J is part of the
UDF/UDF2 filesystem. I should not use SU and GJournal at the same
time. What are the advantages of SU/US+J? What is the advantage of
SU+J over SU? Should I use Gjournal or SU/SU+J? Any hints welcome! :-)

If I have already created UFS2 with -J, I understand I can switch it
off, can I then simply turn of UFS+J (-j) with no data loss on
existing filesystem?

Which solution is better for drives >1TB when I dont want to wait an
hour for fsck?

[1] http://www.freebsd.org/doc/en_US.ISO8859-1/articles/gjournal-desktop/index.html

Thanks! :-)
Tomek

-- 
CeDeROM, SQ7MHZ, http://www.tomek.cedro.info