[Dovecot] remote hot site, IMAP replication or cluster over WAN

[ml at eulberg.name]

Stan Hoeppner wrote:
> IMO, the best way to do high availability is to use an active/active 
> cluster of any number of nodes you see fit to meet your performance 
> and reliability needs.  All hosts are live all the time and share he load.
> When one goes down client performance may simply drops a bit, but 
> that's about the extent of the downside.
> 
> It's inherently more straight forward to setup than the previous 
> scenario, especially if you're using NFS storage.  In this case, you'd 
> build two identical Dovecot servers and have each mount the same NFS 
> mail directory.  Read the list archives for ways to mitigate the index 
> file issue.  Timo wrote a new director specifically to meet this need.
> 
> Two other options for the shared storage are a fiber channel or iSCSI 
> SAN, or using DRBD to mirror disks (or logical devices--RAID) over the 
> network.  Both of these solutions require using a cluster filesystem 
> such as GFS2.  These can be quite a bit more difficult to setup and 
> get working properly than the NFS method, especially for less 
> experienced sysadmins.  They can also be more difficult to 
> troubleshoot, especially for sysadmins lacking sufficient knowledge or 
> aptitude with regard to storage hardware and low level Linux device
drivers.


Stan, what do you think about GlusterFS or Ceph? I am looking for a high
available AND scalable solution based on distributed/replicated storages
(maildirs).
I am not talking about a simple NFS export or something like this.

A real-time replication managed by dovecot would surely be the best way to
keep data in sync  and balance clients.

--
Sven