Recently, I was working on a backup solution for a VMware vSphere environment. Veeam Backup and Replication was the software of choice. Veeam Backup and Replication is entirely based on disk-to-disk backup, but one of the customer requirements was to also have data on tape. For that reason, the backup server was a physical server, so it could be connected to a tape library.
The shared storage of the VMware cluster was based on iSCSI technology, in fact a couple of Dell PowerVault MD3000i boxes. In that case Veeam recommends for data retrieval the “Direct SAN access” mode. The operating system of the backup server is Microsoft Windows 2008 R2 Standard edition. The server has two NICs available for accessing the iSCSI storage.
My first attempt to configure the Windows 2008 R2 iSCSI initiator did not match my expectations. During the first run of Veeam Backup & Replication, LUNS configured for Storage Controller 1 were moved to Storage Controller 0, causing the famous Warnings “LUN not on preferred path”.
Luckily, I found this article on the Dell Storage Wiki, which helped me into the right direction (Thank you very much for that!). The article was written for Windows Server 2003 R2 x_64. In this post, I will step through the process for Windows 2008 R2.
Windows 2008 R2 comes with the iSCSI initiator already installed, which is fine. Do not; I repeat, Do not (as I did during my first attempt) install the Microsoft Windows MPIO. The next screenshot shows the “Add Features Wizard”. This screenshot has been taken after finishing Step 2 (that explains why the “Multipath I/O” option has been greyed out).
Now, you will need the Dell MD300i iSCSI software, you will need the “PowerVault MD300i Resource CD”. A recent version can be found here.
Start the installation. If you also want to install the “Modular Disk Storage Manager”, choose “Typical (Full Installation)”. If you only need the MPIO drivers, choose “Host”.
Curious to see what happened? Go to the Control Panel and open the MPIO feature, it looks like this; a number of Dell devices are now supported.
From the Control Panel, you can start the iSCSI initiator, go to the Configuration tab and copy the Initiator Name for later use.
Now it is time to give the Windows 2008 R2 server access to the MD3000i. Start the “Dell Modular Disk Storage Manager”, go to the Configure Tab and Add the Windows host. Specify the hostname and OS type.
In my case, there is already a Hostgroup available, to provide access to the VMware vSphere servers. Because the Windows server functions as a backup server, I added the newly created host to the same group.
Return to the Windows server and the iSCSI initiator. Go to the Discovery tab. Click “Discover portal” and add the first of four IP addresses of the MD3000i. Repeat this step for the remaining addresses.
Now, go to the Targets tab, the MD3000i shows up under Discovered Targets.
The status of the Discovered Target is Inactive. Click Connect, as a result the “Connect To Target” windows appear. Make sure both options are enabled.
Click the Advanced button, the “Advanced Settings” window shows up.
In the Connect Using section, under Local adapter, choose “Microsoft iSCSI initiator” and under “Initiator IP” and “Target portal IP” supply a matching combination, for instance: 192.168.100.76 (host) and 192.168.100.11 (MD3000i).
Repeat this step for the other 3 sessions.
Return to the Targets tab. The status of the MD3000i is now Connected.
Click the “Properties” button, it will show the four sessions.
Click the “Devices” button.
In this example the MD3000i has 2 LUNS available (LUN11 and LUN12). LUN31 is for administrative purposes and does not show up because it is Disk -1 (compare with Disk 2 and Disk 3). Select the first Device (Disk 2, LUN11) and click the MPIO button.
Out-of-the-box, the “Load balance policy” is “Least Queue Depth”. Dell recommends the “Round Robin With Subset” policy. Note that two paths corresponding to the MD3000i controller that currently owns the LUN are Active; the other ones are in Standby mode.
The Details button shows the path details. You are already familiar with that.
Repeat this step for the other Devices.
Thank you for reading, I welcome your comments.