We migrated from Postfix, had our MX records pointed at our old mail server, and our Zimbra server receiving mail from it. Since we moved the MX records to point to Zimbra we have started to have performance issues and we think it is related to botnet spam attacks and actual spam. Our graphs show huge increases in spam since.
My question is, will we notice larger performance gains by setting up a separate Zimbra server as an MTA over just pointing the MX records back if our performance problem is mostly file system? The web client was slow before we moved the MX records but, now it is painfully slow.
Another question, do we need to purchase anything additional to have two servers or will our current network license work on a split setup?