Hi EveryoneWe are currently using Exchange 2003 SP2 - we have a couple of mailbox servers, each with 4 Storage groups each. Each Storage Group has 4 Mailbox stores. Therefore we have a total of 32 Mailbox stores.With Exchange 2007, we are looking into one Mailbox store per Storage Group. As such, we'll need to increase the number of Storage Groups (we are looking at about 60 altogether).Since we are almost doubling the amount of Mailbox stores, we want to ensure we keep users of the same department on the same store to take advantage of Single Instance Storage.We are, however, planning on giving all mailboxes a 1GB limit as opposed to 100MB which it is currently. Additionally, we are going to be moving a whole load of mailboxes that are currently located in a different part of the country which will double the amount of mailboxes we currently hold.Are there any recommended numbers of max users/sizes of databases/storage group log locations for Exchange 2007?Any pointers I should take into account?Thanks.

Hi Yoshi,~ Recommended database size limit is 100 GB in case you are not use any kind of continuous replication & 200 GB if you are using LCR/CCR.White Paper: Planning for Large Mailboxes with Exchange 2007http://technet.microsoft.com/en-us/library/cc671168.aspx#~ That's nice decision and recommendation too, to keep one mailbox database per storage group and helps you incase you need to enable continuous replication in future. But you can create maximum 50 storage groups on an Exchange 2007 server Enterprise edition.~ It is recommended to keep all transaction logs separate from database derives to any common LUN or on separate LUNs for eachstorage groups...Suggest you to read below article while planning mailbox and database sizeMailbox Server Storage Designhttp://technet.microsoft.com/en-us/library/bb738147.aspxAmit Tank | MVP - Exchange | MCITP:EMA MCSA:M | http://ExchangeShare.WordPress.com

Hi AmitThanks for replying.We are actually thinking of using SCC - do you know what the max recommended size limit is for that? The link mentions continous replicaton (200GB max)and non-continous replication (100GB max) - is SCC considered non-continous?Also - regarding how to calculate the actualdatabase size. Thefirst link states;"Maximum database size should always be calculated as follows: Number of mailboxes Maximum mailbox size = Database size."However, the second link states that the actual mailbox size is comprised of;Mailbox Size = Mailbox Quota + White Space + (Weekly Incoming Mail 2)So, using this, your maximum mailbox size is actually greater than the quota.What I am actually trying to do is figure out how many mailboxes we can get on a database if the limit is 100GB.If we have a quota of 1GB and we have, say, 100 users on the store, does this mean the max database size will be 100GB, or do we need to factor in white space etc?And regarding the 100GB limit - should we actually be aiming for for far less than that, or will 100GB work ok?Thanks again.

HiYoshi,Yes,SCCis non-continuous but still if you enableLCR/SCRon the storage groups ofSCCthen it considered as continuous replication becauseLCR,CCR&SCRare various continuous replication methods and you don't have to restore DB from the backup by considering your DR strategy...I would suggestCCRoverSCCbecause in case database corruption or SAN failure (where shared DB stored, I agree that chances are less) occur, you need to restore the database from backup while inCCR youhave two different copy of DB on both node and in case first DB gets corrupted then you should have second good copy. Does it make sense? Of course, ultimate decision is yours but I am just explaining the ways to reduce downtime or maintain yourSLA:)Yes, total mailbox DB size is, mailbox quota + white space + weekly incoming mails x 2 but you will see white space and weekly incoming mails starting after sometime when users start deletingemailsand pass the retention period then that space will be converted into white space (you can keep an eye on event log 1221 for it)...Best practice is to keep database between 50-100GBafter calculating above factors and it is basically to reduce the downtime while restoring or running maintenance of your DB and not to breakSLAof email service...AmitTank |MVP- Exchange |MCITP:EMAMCSA:M |http://ExchangeShare.WordPress.com

Supplement: Mailbox Store Capacity section in Storage Design for Exchange Server 2007