[Dovecot] Questiosn about dbox

[Javier de Miguel Rodrí­guez]

Hello

     I have read carefully about dbox 
(/http://wiki2.dovecot.org/MailboxFormat/dbox/) and I have some questions:

     - One of the main advantages (speed wise) of dbox over maildir is 
that index files are the only storage for message flags and keywords. 
What happens when we want to recover some messages from backup? With 
maildir we can rebuild message indexes, but I am not sure about dbox. 
Should we also restore "old indexes" and  merge with the "new indexes" 
in order to restore the deleted messages?


     - The previous question applies to sdbox and mdbox. In the case of 
mdbox, we can configure rotation of files using /mdbox_rotate_size/ . We 
would like to rotate daily, not based in size (our users ask us for 
yesterday's backup). How can we accomplish this?


     We have now 17.000.000 messages in our maildir, almost 1.5 TB (zlib 
compresssion enabled). Our backup time with bacula is rather bad: 24 
hours for a full backup, most of the time the backup is busy fstat'ing 
all those little messages. We think that mdbox can help us in this. Does 
anybody has good experiences migrating from maildir->mdox in "large" 
enviroments? What about mdox performance & reliability?

     Thank you for your support

     Javier