[Dovecot] Load Balancing and HA

Hello,

I've been thinking about the best way to achieve load balancing and making my mail servers highly available. So far I believe I have 2 scenarios:

Scenario1: This should allow any to lose any of the servers and clients still have access to their emails (although I am not sure how the indexes would react to this and sudden disconnection)

•      2 Dovecot Proxy servers, using a virtual IP to where the clients

  will connect to from the WAN and LAN

•      2 Dovecot+Postfix servers with local cache

•      2 NFS servers and synced with dsync (mirror, 1 server writes to

  its own NFS and changes synced to the other via dsync)

Scenario2: Pretty much as above on the back end. However, with this there is no way to load balance users.

•      2 Dovecot+Postfix server with local cache

•      2 NFS servers synced with dsync

•      Make use of DNS MX record priority to provide access to secondary

  email server

Anyone care to comment?

Thanks.

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