I have vmware which hosts my Exchange 2010 on an NFS volume which is on Netapp 2040 storage system. I created two iscsi LUNs for Exchange Databases and Logs. I mounted these two LUNs through Vcenter and Thick provisioned. Installed Snapdrive and Snapmanager for Exchange. When configuring SME I get an error message "Failed to get the Exchange information from server SERVERNAME. [SnapDrive Error]:Unable to locate the active LUN drives on this system."
My question is how should the data LUNs be added to the Exchange 2010 server, which is a vm host, for SME to be able to see the LUNs?
Your going to need to mount the LUNs via the vm instance that is your exchange server. I'd install Microsoft's iScsi initiator software then mount the LUNs using SnapDrive to make it work. I'm not sure what version of SnapDrive you're utilizing but here is a link on the NOW site to the Admin guide for 6.3 it has the steps needed to establish the iscsi connections outlined.
Another possibilities is that you can use iSCSI LUN as RDM via ESXi hosts. In that way ESXi hosts will see the RDM iSCSI Lun as a local disk.
This works perfectly if you use VMWare Site Recovery Manager for Disaster Recovery (SRM will see the RDM and attach them to the DR VM). In this case you should have the RDM iSCSI and VM Boot disks on the same controller.
Last time I configured storage for an Exchange 2010 environment we went with the RDM option in Francesco's post. I think from memory you also need to store the RDM pointers (rdm.vmdk files?) on a VMFS (iSCSI/FC) datastore. These get created when you map the LUNs in SnapDrive. What we did was create a small VMWare iSCSI datastore for the Exchange VM and then mapped a couple of LUNs via RDMs to the VM in physical compatibility mode (they come up as local disks on the VM) to allow SnapDrive and SnapManager to manage the LUNs on a FAS3140 (as above all LUNs need to be on the same controller).
As I mentioned you can use SnapDrive for Windows to do the mapping of the LUNs for you, (it also creates the RDM files for you when attaching the disks to the VM) which is handy because you will need it for SME anyway. This method does not require the Windows iSCSI adapter because the VM sees the disks as local devices.
I would also recommend storing one Exchange database per LUN and one LUN per volume if you can to minimise any potential performance impacts while taking backups. There can be a bit of a hit on your Exchange server (and the array) because SME has to make sure the database is in a consistent state for the snapshot. This also makes it easier to grow volumes and LUNS later as your Exchange environment grows .
Yes an iSCSI VMFS is needed to save the RDM descriptors. Regarding luns, the one that will have windows partition in our case are Windows-GPT LUN. I think you can create the LUN directly from SnapDrive (not sure we did some time ago). With the old version of snapdrive there was also some kind of bug in the initiator group creation/mapping. Not sure if we have created the initiator manually or had SnapDrive create it.You can find the RDM LUN creation into the snapdrive admin guide (from page 108). When you have the new lun you can use SnapManager to move the data between local VMDK and RDM disk.
One warning, make sure all ESX hosts can see the RDM LUN directly and the RDM VMDK Datastore or you'll not be able to vmotion the server. If you add an host it should have access to those LUN too.