I am planning a new exchange 2007 system. I have 100 users and would like to give them each a 10G mailbox. Is this reasonable? How much disk space do I need for my system? thanks!

Joe, You should think about making multiple databases this to prevent that if one database has an issue not all users are effected with it. You can define 10GB quota's on the mailbox, but this can be set with different settings such as prohibit sending and receiving mail or prohibit receiving mail. Depending on that you should choose your storage which is needed. I think 10 GB is a reasonable size for a mailbox some companies 2 GB but this is different for each company. Regards, Johan

Like Johan said, have you considered how you will carve things up? For example, if you plan on implementing CCR, then Microsoft recommends a maximum database size of 200GB. Also, your disk space requirements will need to include additional factors such as deleted item retention, especially if your users run up to the 10GB limit. Plenty to think about here.

One additional point, use different storage group for each database. It would be easy for backup/recovery. Transaction logs will be different for each storage group. If you wish to enable LCR / SCR then you can enable for single storage group where VIPs are sitting.

As a person who has been running large and small Exchange systems for over a decade now, I can honestly say 10gig is insanely large. Most corporations were well below 500meg a mailbox before Exchange 2007 came out. I would STRONGLY encourage you to limit the size of your user mailboxes to 1-2 gig in size to start off with. You can always increase the mailbox size if you need to, but trying to take away storage from users is extremely hard. And for the record a 1 gig mailbox is HUGE. Larger than most people realize. The number 1 problem with mailbox sizes is people sending attachments back and forth until the cows come home, andnever cleaning out their sent items. So keeping this in mind, a larger mailbox size limit only delays users from having to clean up their mailboxes. If they never want to clean out their sent items, but want their mailboxes small, then vaulting looks to be a better and more efficient long term solution. The other problem with a 10gig mailbox is that it would take an etremely long time to sync in cache mode. One of MSFT's own staff posted an article about how the only way he was able to make an extra large mailbox usable in cache mode was to turn off certain sub-folders for synchronization. So please do yourself a favor and reconsider the 10gig mailboxes, and start with 1gig where you can always expand from there.