Ocfs2 users - Oct 2011 - is it wise to enable these features on old volumes?

(This is separate from the discontig-bg discussion)

Several two-node clusters. 64 bit Oracle Linux. QLogic fiber channel. 
Pillar Data SAN.

Our old volumes have these features:

Compat: backup-super
Incompat: None
RO Compat: None

A newly-created FS under 1.6 (I tested it with a 100 MB loopback file) 
has these features by default:

Compat: backup-super strict-journal-super
Incompat: sparse inline-data
RO Compat: unwritten

We have an image files volume, with lots and lots of little files; 
inline-data sounds like a good idea.
We have a logs volume, with lots of files in a single directory; 
indexed-dirs sounds nice in that case (but it's not enabled by default 
on a new volume).
unwritten sounds like it could give an overall performance boost.

I am tempted to enable these features, but I am wondering about the 
wisdom of doing so. If these were new volumes created under 1.6, I'd 
have no qualms. But these volumes have been created quite some time ago, 
and used heavily every day.

I may get some performance boost by enabling them, but would I give up 
any stability?

Also, enabling the features, is it an online process, or does it require 
unmounting the volumes from all nodes?

-- 
Florin Andrei
http://florin.myip.org/