Store size limitations (Full Version)

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Teknoah -> Store size limitations (3.Nov.2003 10:10:00 PM)

Top of the day to you all,

We are currently planning our exodus from 5.5 to Exchange 03' and have a concern about max storage for Standard and Enterprise.

Our current Exchange 5.5 has approx 11GB now but no compress has been performed in some time and we plan to do one prior to the migration. However we are concerned that when we perform the mailbox move that we will lose single instance storage of attachments resulting in an unwanted bloating of the IS. Pub storage is around 3GB and we are concerned that we may hit the 16GB limits as a result of the move if the storage limits is the sum of the 2 stores. We have a lot of BLOB's stored in our mail server with little or no hope of moving it elsewhere. Frankly, I'd rather migrate the users somewhere and keep my 5.5 after cleaning it up but we know that isn't going to happen. so........

Q1: Is the storage limitaion that is imposed on standard the sum of the 2 stores?

Q2: Will we lose single instance with the MB move?

Q3: where can I find some documentation on the aforementioned questions? I have searched the web to the point that my right eye will not stop twitching and I have yet to see anything other than a statement that says Standard get 16GB.

Thank you in advance.

Teknoah -> RE: Store size limitations (4.Nov.2003 4:12:00 PM)

Since my post I have discovered that Exchange 03 Standard allows 2 storage groups but I am still not sure if a storage group consists of the pub and mail stores.

Also, in the event that 1 storage group is inclusive of pub and priv. can the 2nd storage group host mail for the same smtp domain or is it's intent to allow for mail service to 2 disparate domains.

Teknoah -> RE: Store size limitations (4.Nov.2003 4:36:00 PM)

Ok. well first i am talking, typing, to myself and my eye has not stopped twitching so i am definitely in the IT biznez but I do have good news and no it doesn't have anything to do with saving money on insurance.

I have found a deployment doc that covers the question I have brought to and answered by myself, but hey that is ok at least I can help myself. 1458-4809-97D6-50D8AEEBD8A1&displaylang=en

So now I am down to a new set of questions.

Q1: 1 storage group can have 2 databases for Exchange 2003 Stdrd Ed, are the 2 db's the priv and pub or are the public folders and mailboxes considered 1 db?

Q2: Is it possible to move mailboxes without loosing single instance of attachment storage?

Thanks in advance,


[ November 04, 2003, 04:55 PM: Message edited by: Noah ]

VRHR -> RE: Store size limitations (10.Nov.2003 1:54:00 PM)

Q1: Public folders and mailboxes are each considered seperate db's. So you have one db available for your mail.
Q2: Unfortunately the single instance storage is lost (using the migration wizard) because mail is migrated on a per mailbox basis.

Good luck,


Teknoah -> RE: Store size limitations (10.Nov.2003 4:39:00 PM)

Correct they are seperate DB's but both are members of the Information Store and would like to know if the Logical size limitations "IS" is the sum of the 2 DB or if each DB may have a logical limit of 16GB.

Someone please chime in on this as solid documentation is very difficult to find. Thank you in advance.

[ November 10, 2003, 06:56 PM: Message edited by: Noah ]

rbezenek -> RE: Store size limitations (2.Mar.2004 1:04:00 AM)


According to the documentation that I have found:

"The Standard Edition supports one mailbox database up to 16GB."

Now, given all the other literature that I have read on Exchange 2003, MS defines a mailbox database as the priv.edb and the priv.stm (used for MIME).

I would, given these two data points, feel confident in stating that the Public Folder information is not taken into account when calculating the limitation of 16GB placed on the the mail store object. The one caveat here is if in the future you will mail enable any of your Public Folders...and in that case you will be using private store space for that information.

Now, if after reading this, you are still uncertain about which direction you should take (and believe me with MS I would be too!), I would go through your Exchange 5.5 administrator and look at the resources each mailbox takes up. You can export this information to an Excel spreadsheet and then sum the mailbox usage. This will give you a very precise and accurate picture of how big your priv.edb will be since you will be breaking your single instance storage capabilities when you migrate.

So, armed with this information you can then sum that data with the expected size of your public folder store to see how close you will be to the 16GB ceiling.

I know how crazy this can all be as I am, too, in the middle of planning an enterprise upgrade and rollout of Exchange 2K3. So, good luck and I hope this all helps.

Ryan Bezenek
Network Design Specialist

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