fsck background mode for gbde crypted disc?

Hi

I wonder if I can do a background check after mounting an crypted part 
or does the check have to be b4 ?

best regards,

Christophe
-- 
Christophe Zwecker                     mail: doc_at_zwecker.de
Hamburg, Germany                        fon: +49 179 3994867
http://www.zwecker.de

"Who is General Failure ?  And why is he reading my disk ??"