[Dovecot] Question about indexes and maildir/sdbox/mdbox

[Javier de Miguel Rodríguez]

Hello

     We are now running dovecot 2.0.9 with indexes in a ram disk and 
maildir storage in a test system. We have the following questions:

     - If there is a power outage / kernel crash, we will lose the 
content of ramdisk. We have tested that indexes are regenerated when a 
user logs in via imap, so e-mail access will be "slower" after a power 
outage / kernel crash, but everything should work as expected (TM). Are 
we missing something?

     - We are evaluating migrating from maildir to dbox. There are two 
alternatives: sdbox and mdbox. Reading about dbox in the wiki 
(http://wiki2.dovecot.org/MailboxFormat/dbox) we see that using a ram 
disk for indexes for mdbox is a really bad idea:

/"Note that with dbox the Index files actually contain significant data 
which is held nowhere else. Index files for both *single-dbox* and 
*multi-dbox* contain message flags and keywords. For *multi-dbox*, the 
index file also contains the map_uids which link (via the "map index") 
to the actual message data. This data cannot be automatically recreated, 
so it is important that Index files are treated with the same care as 
message data files."/

     So in mdbox we should not use a ramdisk for indexes. But what about 
sdbox? sdbox indexes work as maildir indexes? Are sdbox indexes bigger 
than maildir indexes?

     Thank you very much for your support

     Regards

     Javier