I dont think there is a good way we can really give any good options. For example, we run a few SM servers for some clients, while one client has ~230 users, another client has ~270, the client with the 230 users is big strain on their server because they are extremely active, they use every single little feature SM has and really push it, while the ~270 client user really just sends some emails here and there etc. maybe a little contact usage, some light calendar etc.

I think it just comes down to how the users will use the server, start with what you think may be a good balance and adjust from there.

We use a VM in our configuration.

Using a pretty large scale VMware (v6) implementation.

We are running 260 domains with some 3,000 or so mailboxes total on the Enterprise Edition of SM.

We average about 32,000 incoming and 15,000 outgoing message a day currently.

SmarterMail VM config:

- Win 2016 Std x64

- Mem: 16G

- Proc: 2x 3.5GHz 

- Single NIC 1G

User perceived speed is quick on nearly all operations in that configuration and load.

Hope that assists someone in planning.

Rod

ps.  I should add... we DO NOT use the on system anti-spam / anti-virus for anything other than intra-server operations.  All our inbound and outbound mail runs through a front-end AS/AV server to handle that scanning.