I'm planning for a E2K7 migration next year, and I'm trying to determine disk space requirements for the Hub Transport and Client Access roles. I'm planning for approximately 2,000 medium to heavy use mailboxes, and based on current size plus historical growth patterns, I've determined that my mailbox server roles need to have (or will need to have by end-of-life) around 1.5tb of disk space. I've been able to find sizing guides for the mailbox & edge transport roles, but can't seem to find it for the hub transport & client access roles. Since these two roles only temporarily store messages, I'm guessing that 10% of the mailbox server size should be more than sufficient. Am I on target here? Thanks in advance! JAllenLSI

Hello JAllenLSI, This information can be found at Exchange Help and there are also some examples from Microsoft on the same documentation. http://technet.microsoft.com/en-us/library/bb124518.aspx

Thanks for the quick response! I had read most of this article, but apparently not enough! JA

here is another one http://msexchangeteam.com/archive/2007/02/26/435846.aspx