As my my understanding SIS or SIC in Exchange will store a copy of mail and sends pointers to all the users in the same database. Please correct me whether it is done at the database level or Server Level. Also where this mail is stored and pointers are send.Is it in the forst mailbox or do we have any seperate storage for it.Ahmed Ali

SIS is done at database level. To make it simple, Mails are getting stored in the DB but only one copy exits though multiple recipients has that mail.Shaba

SIS is done at database level. To make it simple, Mails are getting stored in the DB but only one copy exits though multiple recipients has that mail.Shaba

Thanks Shabarinath, Is Database capable of storing Mails and attachment. How much storage can a database have, as we will set limits only to mailboxes. Please clarify.Ahmed Ali

Hi, In Exchange 2007, attachments are single instanced, but message bodies are not. See: Single Instance Storage in Exchange 2007 When you calculate your storage space needs, don't include SIS. It is impossible to know how much space SIS will save you, if any. Extra Info: SIS was removed completly in Exchange 2010. See: Dude, Where's My Single Instance? Martina Miskovic