I need to move database from currently on 8 filesystems
to new 6 filesystems on the same server
How do I rebalance the data on 6 containers?

redirected restore..when you do a redirected restore, you have an option to redefine tablespace containers..point them to new filesystems..

or export the data in the tables to a dir
extract ddl for db using db2look
modify the tablespace ddl using the new filesystems as containers
save db cfg
drop the db
recreate db
execute the ddl
load the data back
run set integrity
reset db cfg parameters

backup db
reswore db with redirect

Other alternatives are to use RELOCATEDB, ALTER TABLESPACE DROP CONTAINER …
Sorry, but your may have to give more details like version, operating system, container layout (say, you have 8 containers and want to reduce to 6 containers, or you have some tablespaces with containers that are in the file systems) to see if these will be any good

Sathyaram