[horde] Some question

[Fabio Pedretti]

Hi, I have some doubt for these:

1) Virtual File Storage: what difference there are and which is the preferred 
between "Files on the local system" and "SQL database"?
2) Custom Session Handler: what are the differences and which is the preferred 
driver?
3) How can I mark a shared address book (on an LDAP server) only readable by 
turba for all users (seems before turba 2.1 was to set 'readonly' => true in 
sources.php)? Someone explain me that I should use the permission but I can't 
figure how to use it.

Thanks,
  Fabio