We have a customer condering SnapManager for Exchange, which will require SnapDrive for Windows. They will be using iSCSI protocol for data access. I realize that for multipathing on the Windows hosts, the customer could use Microsoft's multipathing, but from the reading I do, it seems like NetApp DSM for Windows MPIO will be a more robust solution. My questions are:
1) Does the NetApp DSM software include both FC and iSCSI drivers?
2) Does installing SnapDrive require multipathing on the host? (my understanding is that it does)
3) Does the SnapDrive software include the NetApp DSM software or does it need to be licensed separately
For (1), NetApp's most recent MPIO DSM 3.2R1 package supports FCP and iSCSI.
For (2), SnapDrive itself doesn't require MPIO on the host. A Windows server could use SnapDrive over a single iSCSI/FCP connection to a NetApp controller without MPIO. If you are implementing a production configuration, however, multipathing (MPIO, MCS, etc.) should be a part of the solution. I would strongly recommend reading TR3441 for multipathing possibilities. Since you mentioned SnapManager for Exchange (SME), you will need SnapDrive, the Windows Host Utilities Kit and some form of multipathing.
For (3), the NetApp DSM was included as a separate licensed feature in older SnapDrive (before 4.2) packages for both iSCSI and FCP environments. As of SnapDrive 4.2 and later, the NetApp DSM was separated out of SnapDrive into its own licensed package.