[Dovecot] Great time savings backing a mdbox versus Maildir

[Javier Miguel Rodríguez]

> Oh.. I envy you. Will probably need to do the same at some point, but
> I'm having problems understanding how we will ever be able to make the
> transition. Too many files -- too many users..
>

     We did the transiction via imapsync: we had /"the old server"/ and 
a /"new server"/, and we migrated all mailboxes
with imapsync and master user feature. The first imapsync takes a lot of 
time, but the next ones are incremental, and take much less time. When 
we are ready (a night) , we stop we switch from "old server" to "new 
server". Minimal downtine, and if everythings goes wrong, we can 
imapsync "in the other way", from new-> old instead old->new


     Our mail servers are virtualized in a  vmware vsphere cluster. We 
have HA & DRS, and all the info is stored in the iSCSI SAN. Ir our setup 
we "only" have a virtualized mail , but if the hw node fails the 
virtualized starts automatically in another ESX.

     Regards

     Javier

> How long did it take to convert from maildir to mdbox, how much downtime ?
>
> Do you have a clustered setup, or single node? I'm wondering how safe
> mdbox will be on a clusterfs (GPFS), as we've had a bit of trouble with
> the index-files when they're accessed from multiple nodes at the same
> time (but that was with v1.0.15 -- so we should maybe trust that such
> problems has since been fixed :-)
>
>
>    -jf