I am planning to upgrade from Exchange 2000 to Exchange 2003. I am trying to determine if I need to go with Enterprise vs. Standard edition. We use Public Folders extensively and I had to deploy a second Exchange 2000 server because of the database limits. I originally tried to add a second store on the same server, but it wasn't visible via Outlook. At that point I had to go with a second Exchange server. I would like to go back to 1 Exchange server. The 75 GB limit should be enough given that we are around 28GB now (2 public stores each on a separate server). However, if we outgrow that, could I add additional Public Folder stores that would be visible in Outlook? I am also hoping that I can utilize my NAS to house the Databases. Is that possible with both Standard and Enterprise? Given my "wants" which is the best fit, Standard or Enterprise?

With Exchange 2003 std you getonly one mailbox database and one public folder database each up to 75GB, so I think you're OK NAS can be used if you can connect to it with iSCSI protocol, you cannot map a disk over network and then let exchange use it. why not go for Exchange 2007?

Dear customer: From your post, I noticed you mentioned, I originally tried to add a second store on the same server, but it wasn't visible via Outlook. Please check which public folder tree you linked to the second public folder store, if it was linked to the tree whose type is general purpose, it is normal. Because there are two types of trees which can exist in an Exchange organization; MAPI trees and General Purpose trees (also known as non-MAPI or Application trees). The MAPI tree is the only tree which is exposed through Outlook; Application trees are not visible from a MAPI client. If you want to add additional public folder store that is visible to Outlook client, you cant do it on the first Exchange server, you must do that on the second Exchange server, because the first Exchange server has linked its public folder store to the MAPI tree by default. Microsoft generally recommends that you use a DAS or SAN attached disk storage system (for example, small computer system interface [SCSI], Fiber Channel, or integrated device electronics [IDE]) to store your Microsoft Exchange 2000 Server or Microsoft Exchange Server 2003 database files, because this configuration optimizes performance and reliability for Exchange Server. If access to a disk resource requires that a share be mapped, or if the disk resource appears as a remote server by means of a Universal Naming Convention (UNC) path (for example, \\servername\sharename) on the network, the disk storage system is not supported as a location for Exchange Server databases. For more information about Exchange Server and network-attached storage, please refer to the following information: Exchange Server and network-attached storage http://support.microsoft.com/default.aspx?scid=kb;EN-US;317173 Support for iSCSI technology components in Exchange Server http://support.microsoft.com/default.aspx?scid=kb;EN-US;839686 Microsoft support policy on the use of network-attached storage devices with Exchange Server 2003 http://support.microsoft.com/default.aspx?scid=kb;EN-US;839687 Hope it helps. Rock Wang - MSFT

I have some 3rd party apps that don't work with Exchange 2007 yet. Thought I would take the first step to 2003 and then upgrade when they were ready. How do I know if my NAS supports iSCSI? Hardware vendor?

Is the MAPI tree limitation the same with Standard and Enterprise?

with MAPI tree i think you are talking about Public Folder tree?

Dear customer: For more information about iSCSI hardware that has passed the Designed for Windows Logo Program, visit the following Microsoft Web site: http://www.microsoft.com/WindowsServer2003/technologies/storage/iscsi/default.mspx Of course, you can also consultant your hardware vendor. Yes, no matter whether it is Standard or Enterprise version, the MAPI limitation is same. Although there can be only one MAPI clients folder tree per organization, there can be several general purpose folder trees per server. For more information about public folder tree, please refer to the following documents: Description of public folder tree types in Exchange 2000 Server and in Exchange Server 2003 http://support.microsoft.com/kb/258509/en-us How to create a new public folder tree and store in Exchange 2000 Server and in Exchange Server 2003 http://support.microsoft.com/kb/255077/en-us Hope it helps. Rock Wang - MSFT