HP has released a new version of the Sizer for Exchange. The tool makes it very easy to find suitable hardware for an Exchange 2013 organization. Similar to the Mailbox Calculator, the parameters can also be defined quite precisely in the HP tool. The Sizer then recommends which HP hardware is suitable. The HP Sizer for Exchange 2013 can be downloaded here:
http://h71019.www7.hp.com/ActiveAnswers/cache/70255-0-0-0-121.html
I have not yet found anything from the other server manufacturers. Does anyone know of similar tools?
