On Wed, 11 Jul 2018, mj wrote: > If you consider ceph as "the cloud", this could also apply: > https://github.com/ceph-dovecot/dovecot-ceph-plugin Maybe the OP will find the following article interesting http://www.admin-magazine.com/Archive/2015/26/Scalable-mail-storage-with-Dovecot-and-Amazon-S3 Joseph Tam <jtam.home at gmail.com>