I am faced with an ever growing mail spool and increasing number of mailboxes. A move from courier to dovecot helped the situation as dovecot uses more efficient indexes but I'm bond to outgrow my current shared-storage. So, as shared-all does not work any more, I need to move to a shared-nothing backend storage, unless I want to shell big $$$ for a custom solution, which I don't. The obvious move would be to glusterfs based storage (perhaps easiest). However I'm wondering if glusterfs deployed on 3-4 nodes would be sufficient. There's also ceph, which is inherently more resource-hungry. And there's hadoop and hdfs, which might be usable with dovecot. I have not found much information about hadoop native dovecot plugin, but perhaps it's usable di hdbase. I'd just like to exchange some ideas with the smart guys using ispconfig in bigger installations. What do you use? ispcomm.