[Dovecot] Best way to change index location on mdbox

[Patrick Westenberg]

Timo Sirainen schrieb:

> You must not lose indexes with mdbox or you'll lose message flags and
> mails may also end up going to wrong mailboxes.

Yes, have been there but this behaviour is confusing me as I find 
conflicting information in the wiki:

http://wiki2.dovecot.org/IndexFiles
"If index files are missing, Dovecot creates them automatically when the 
mailbox is opened."

http://wiki2.dovecot.org/MailboxFormat/dbox
This data cannot be automatically recreated, so it is important that 
Index files are treated with the same care as message data files.

So why do I lose mails if I delete index file but if e.g. a director
connects to a backend with non existing index files yet, they are created.