The Lenovo Storage V series products consolidate storage capacity for Lenovo and non-Lenovo application host systems using the Fibre Channel and Fibre Channel over Ethernet, or FCoE, protocols. In this e-Learning module, you will learn about the role hosts play within your environment, the steps to configure hosts, troubleshooting tips, and additional resources you can use to find more detailed information.
In most Lenovo Storage V series products, each control enclosure contains disk drives and two node canisters, and the two nodes in the same enclosure form an I/O group. In the IBM SAN Volume Controller product, or SVC, each node is an individual server in a system, and two nodes form an I/O group. The I/O groups present volumes to host systems. These host systems connect to the volumes and read data from them or write to them, using the SCSI command set. This e-Learning module focuses on Fibre Channel and FCoE host-attachment methodologies.
A storage area network, or SAN, uses switches, switch fabrics, and switch zones to connect host systems to storage devices. To provide redundancy, use two fully independent counterpart SANs. Use Fibre over Ethernet connections to connect each host and the product to the local area network, or LAN. Multiple Ethernet connections between the LAN and the product also help ensure redundancy.
There are several steps to complete when configuring a Fibre Channel or FCoE host. First, you need to configure the host and the switches, and then set the zones for the host system. Next, use the management GUI to create the host object, select the I/O groups, and map the volumes to the host. Finally, you work with the host system to discover the new disks. Let us look at each step in more detail.
To configure a host, you need to first install the appropriate host bus adapter, or HBA, and the HBA driver on your host system. Then, install and configure the appropriate multipathing driver for the host system. For details about how to perform these steps, and to verify that the host operating system, HBA, and device drivers are all supported, see the Host attachment topics in the information center.
To define host zones, you must configure the switches. To set up redundancy, configure two separate switch fabrics. The two different fabrics can be created from switches of different vendors. Each vendor might have a different suggested configuration process, so check the documentation carefully.
Each host zone should consist of one port from each node and one host Fibre Channel port. Zoning prevents the hosts from directly accessing external managed disks and potentially corrupting the data that is stored on those disks. Some hosts can be configured to only access a subset of the I/O groups in the system, so you might need to reduce the number of nodes in a zone to match such a configuration. Host configuration is discussed in more detail later. Note that the zoning configurations are applicable to both Fibre Channel and FCoE connectivity.
FCoE is the transport or mapping of encapsulated Fibre Channel frames over Ethernet. Fibre Channel frames are encapsulated as-is inside Ethernet packets and transmitted using a combination of Converged Enhanced Ethernet, or CEE, switches; FCoE switches; Fibre Channel Forwarders; and existing Fibre Channel switches to the target device. Fibre Channel Forwarders, or FCFs, have both Fibre Channel and Ethernet ports. FCFs allow Fibre Channel hosts to connect to FCoE Storage ports. FCoE ports follow the same zoning rules as Fibre Channel ports. This means FCoE worldwide port names, or WWPNs, NPORT_IDs, or both can be zoned with the Fibre Channel host. Hosts must be connected to the same FCF or FCoE switch. Fibre Channel and FCoE ports on hosts and all Lenovo Storage V series systems can all be part of the same zone. A mixed configuration consisting of both Fibre Channel and FCoE is allowed. Virtual LAN, or VLAN, configuration on FCFs and FCoE switches must be done to ensure FCoE connectivity.
FCoE works on 10 Gigabit Ethernet networks and uses an advanced version of Ethernet networking called CEE that satisfies the requirement for lossless networks. Note that CEE switches are different than traditional Ethernet switches. Each FCoE port of the Lenovo Storage V series system must be connected directly to an FCF or an FCoE switch. In cases where two FCoE ports of the system are expected to be in the same zone, they must be connected to the same FCF or FCoE switch. FCoE connectivity is supported on certain models of Lenovo Storage V series products. You can view WWPN information in the node canister properties. Go to the System Details panel. Select a canister to view detailed information about node status and associated ports. If you are working with the SAN Volume Controller system, expand the I/O group to view its nodes. Select a node to view detailed information about the status of the node and associated ports.
Let us look at the importance of redundancy. When you set up a host zone, multiple connections are established between the host and the system. Within these connections, a multipathing device driver can create multiple independent paths between the host and the nodes inside the system. If one of the paths fails for any reason, the multipathing device driver uses a different path to access the data. This action is known as failover.
When the original path comes back online again, that path is automatically recovered and the multipathing driver can use it again. This action is known as failback. Note that failback is not instantaneous – it can take 30 minutes or more – so verify that all paths are online before performing a service action on the partner node.
For more information about zoning and preferred nodes, see the planning and configuration topics in the information center.
For the next step, open the management GUI and go to the Hosts panel. For each host you create, select Create Host. Select Fibre Channel as the host type.
Enter a name for the host and add one WWPN for the available ports. You can either enter the WWPN manually or select it from a list. If the WWPNs for your host are not displayed in the list, ensure that the host has Fibre Channel drivers installed and is zoned correctly. If you find that the drivers are installed and that the hosts are zoned correctly, but you still do not see the WWPNs for your host in the list, enter the WWPNs manually. Click Add Port to List for each WWPN you select. You can also edit Advanced Settings information. Select Create Host to complete this task. After the host has been created, assign volumes to the host.
Finally, use the host system utilities to discover the new volume disks that will be made available by the product. You also have the option of creating a file system for those new disks. This task is performed on the host system. Instructions will vary depending on your host operating system, so consult your host system documentation for more information.
If you are having problems attaching Fibre Channel or FCoE hosts, here are some tips that might help. The problem might be related to the SAN zoning or cabling. Ensure that the active switch configuration includes the host zone. Check that the host port link is working. To help verify end-to-end connectivity, use the management GUI to go to the Network panel. Here you can view connectivity for nodes, hosts, and storage systems.
The problem might be related to your configuration settings. Check your WWPN configuration and your host mappings. To view your configured WWPNs, go to the Ports by Host panel, and view the Status column of the port you are troubleshooting. If the WWPN is configured correctly, it will be online. To view a list of volumes mapped to a host, go to the Host Mappings panel and ensure that the host mappings are correct. To verify that a volume is online, go to the Volumes panel.
The problem might also be related to the host. Use operating system utilities (such as Windows Device Manager) to verify that the HBA driver and multipathing device driver are installed, loaded, and operating correctly. Refer to the multipathing driver documentation for more information on how to perform this task.
In this e-Learning module, you learned the overall steps to configure hosts in this environment, including tasks that are performed using the management GUI. And, you viewed several items that you can verify when you are troubleshooting host-attachment problems.
To learn more, see the host attachment, configuration, and planning topics in the information center, or visit the Support website.