My employer performed an Exchange 2003 to 2007 migration in early 2008. By the end of that year, the server was filling up and expansion options were limited as all the drive bays in the server chassis were full. In parallel to this was the desire to move anti-virus/anti-spam services in house, thus removing a significant ongoing cost.
The solution proposed by me was to purchase a new server with it having a focus on exceeding current needs and allowing easy expansion, while re-allocating the current server to an Edge Transport role where it could perform anti-virus/anti-spam duties.
The preferred vendor, HP, participates in Microsoft’s Exchange Solution Reviewed Program (ESRP) where vendors create a platform that are certified to perform under a certain workload. The solution I reviewed was a DL185 storage server, which could support 2,000 mailboxes (at the time, there was 1,500). The DL185 had a P800 controller which could allow MSA storage enclosures to be attached to it. Another solution HP presented showed that the P800 controller with three MSA60 enclosures could support over 6,000 mailboxes. Based on this and other research such as calculating the current load, I put forward this option.
The server was installed and about half the users have been migrated to it. Feedback so far has been positive.