innodb_undo_tablespaces in 5.6

we can not use it after upgrade from 5.5 and after clean install. It possible only when we
dump all databases
clean datadir
adding this parameters to config
manualy run mysql_install_db
load dump back.
Is there any possibility to add this options on live server without those hard operations ?
For me, strangely enough the introduction of such a function, which is available only in a very limited number of cases.

Are you referring to this upstream option introduced in MySQL 5.6?
As mentioned documentation explains it works only once, before you actually initialize InnoDB tablespaces, so not possible to change later.

However with
you can limit the number of undo segments that are actually used by transactions, regardless of how many are physically initialized. But it must be always equal or lower number of course.