Hello Timo,
About the dovecot-shared file, the wiki says :
"Unless you're using a single UID for all the users, you'll need to have a dovecot-shared file in each shared maildir. The group and the file permissions for new files inside the maildir are taken from the dovecot-shared file."
but says the following too :
"With Maildir dovecot-shared file controls if the \Seen flags are shared or private. If you don't have the file, they're shared."
The question is "does it make sense (or is it even possible) not to have the file ?". Why would one not have the file and how would it work then ? By relying on the set-gid bit and umask ?
Finally, the wiki says :
"If you do have the file, the \Seen flag state is stored only in the user's index files. By making each user have their own private index files, you can make the \Seen flag private for the users."
So, my undersanding is that :
you have the file 1.a) if INDEX points to the same place, flags are shared but are lost if indexes are lost 1.b) if INDEX points to some user dependant place, flags are private but are lost if indexes are lost
you don't have the file flags are shared, whatever INDEX points to and, since they're stored in filename, survive indexes lost.
but does shared-mailboxes even work if we don't have that file ? maybe only if the set-gid bit and umask does what the file would have done ?
So maybe, if you want to share flags, 2) is safer dans if you want them private, 1.b) is the only choice ?
thanks
-- Thomas Hummel | Institut Pasteur hummel@pasteur.fr | Pôle informatique - systèmes et réseau