We are about to migrate to Office 365 E3 plan from Exchange 2010 but the challenge we face in migrating on-premises Archive having around 2TB space and is very important and critical for and must be available to users all the time.
How to move 2 TB archive data> What are the options Microsoft is giving for current archive for cutover migration? Are there any good third party tools available in market?
Does the archive really need to go on O365? Another option would be to store the archive in PST files on the user's local PC's or on a local server/NAS.
Maybe upload the last few months of email to O365 so it is accessible on mobile devices, etc and store the rest locally.
How many users do you have?