Manage storage adapters
A host uses storage adapters to access different types of storage devices. CAS supports SCSI, iSCSI, FC HBA, and FCoE HBA storage adapters.
A host has a default local-SCSI storage adapter and a default open-iSCSI storage adapter. The local-SCSI storage adapter is used to access local disks. The open-iSCSI storage adapter is used to access iSCSI storage. An Open-iSCSI storage adapter has an IQN by default. As a best practice to simplify management and maintenance, change the IQN.
If the host is configured with hardware FC HBAs or FCoE HBAs (for example, CNA) for accessing FC storage, the storage adapter list also displays detailed information about the FC HBAs or FCoE HBAs.
The system also supports software FCoE adapters. The FCoE protocol stack of the host performs protocol processing for software FCoE adapters, and the NIC performs FCoE forwarding. Software FCoE adapters must work with NICs that support data center bridging and FCoE offload.
If multiple paths exist between a host and a SAN storage, traffic can be switched to an available physical link when any element in the SAN network fails, for example, an adapter, switch, or cable. Besides link switchover, the paths can load balance the traffic to reduce or even eliminate potential bottlenecks.
By default, the system applies the multipath policies defined by vendors to their respective storage devices. The system provides four multipath policy types, including most recently used, fixed, round robin, and optimal. You can choose a multipath policy according to the type of a storage device and enable the multipath policy feature on the storage device.
You can configure multipathing for different storage pools on a host as follows:
iSCSI shared file system—When you add an iSCSI shared file system, enter multiple service IP addresses for an IP SAN. If you enter only one IP address, multipathing is still enabled by default. For more information, see " Manage shared file systems."
FC shared file system—When you add an FC shared file system as a storage pool, select multipath for the HBA parameter. For more information, see " Manage storage pools."
iSCSI network storage—Multipathing is disabled by default and is not configurable.
FC network storage—Multipathing is enabled by default and is not configurable.
Operators can scan storage adapters on CVM to discover available LUNs after carving LUNs and configuring LUN mappings on storage servers. To discover the LUNs on iSCSI storage that are assigned to a host, you must add the corresponding storage pools on the host. If CVM cannot discover the LUNs on FC storage for a host, reboot the host.
Prerequisites
Before you configure software FCoE adapters, complete FCoE configuration on switches.
Restrictions and guidelines
ARM hosts do not support software FCoE adapters.
Use the following methods to troubleshoot the creation failure of a software FCoE adapter:
Verify that cables are correctly connected. Click Refresh on the Storage tab.
Verify that the FCF switch is correctly configured.
Execute the shutdown command and then the undo shutdown command on the interface that connects the FCF switch to the host NIC.
If the rate of the NIC for the created adapter is 10 Gbps, the Rate column displays Unknown for the adapter, and the actual rate is 8Gbps.
You cannot delete a software FCoE adapter if its storage devices have mounted storage pools. To delete the adapter, you must first delete the storage pools.
Set the IQN of a storage adapter
On the top navigation bar, click Resources.
From the left navigation pane, select Compute > Host Pool Name > Host Name or Compute > Host Pool Name > Cluster Name > Host Name.
Click the Hardware tab, and then click Storage Adapters in the navigation pane.
Click Set IQN in the Actions column for an open-iSCSI storage adapter.
Enter an IQN, and then click OK.
Add a software FCoE adapter
On the top navigation bar, click Resources.
From the left navigation pane, select Compute > Host Pool Name > Host Name or Compute > Host Pool Name > Cluster Name > Host Name.
Click the Hardware tab, and then click Storage Adapters in the navigation pane.
Click Add.
Click the
icon next to the Physical Interface field.
Select a physical interface, and then click OK.
Click OK.
Delete a software FCoE adapter
On the top navigation bar, click Resources.
From the left navigation pane, select Compute > Host Pool Name > Host Name or Compute > Host Pool Name > Cluster Name > Host Name.
Click the Hardware tab, and then click Storage Adapters in the navigation pane.
Click Delete in the Actions column for a software FCoE adapter.
In the dialog box that opens, click OK.
Configure multipathing for a storage device
On the top navigation bar, click Resources.
From the left navigation pane, select Compute > Host Pool Name > Host Name or Compute > Host Pool Name > Cluster Name > Host Name.
Click the Hardware tab, and then click Storage Adapters in the navigation pane.
Click Edit in the Actions column for a storage device.
Select a multipath policy, and then click OK.
Perform a device scan
On the top navigation bar, click Resources.
From the left navigation pane, select Compute > Host Pool Name > Host Name or Compute > Host Pool Name > Cluster Name > Host Name.
Click the Hardware tab, and then click Storage Adapters in the navigation pane.
Click Scan in the Actions column for a storage adapter or click Scan All.
Select a scan mode and click OK.
Parameters
Add a software FCoE adapter:
Physical Interface: Select a physical NIC that supports data center bridging and FCoE offload.
Configure a multipath policy:
NAA: Identifier of a LUN on a storage server.
Multipath Policy: Select a multipath policy.
--: The default multipath policy. If the system has the default multipath policy for the device, it automatically selects the default multipath policy. If the system does not have the default multipath policy, it selects the optimal policy.
Most Recently Used: Use the path that is used most recently. When the path fails, the host randomly selects another path for I/O. When the failed path recovers, the host does not switch over to the path. You must perform a manual switchover. This policy does not support load balancing.
Fixed: Use the preferred path as long as it is available. If the preferred path becomes unavailable, the host selects another path. When the preferred path recovers, the host automatically switches over to the preferred path. This policy does not support load balancing.
Round Robin: Use an automatic path selection algorithm that rotates through all available paths to distribute I/O among these paths.
Optimal: Use the recommended configuration in Asymmetric Logical Unit Access (ALUA) mode. Paths are grouped based on the storage SP. The path group with the highest priority is selected as the optimal path group. The host distributes I/O among all available paths in the optimal path group for load balancing. When all paths in the optimal path group fail, the host switches over to the backup path group. I/O is also distributed within the backup path group for load balancing. When the optimal path group recovers, the host switches over to the optimal path group.
State: Path state.
IP Address: IP address of the mapped device. This parameter is displayed only after multipathing is enabled for an IP SAN storage device. This parameter is not displayed for FC SAN storage devices.
Active Paths: Available paths for multipath I/O. An asterisk (*) represents an active path. When two or multiple asterisks are displayed, all paths are used for I/O load balancing.
Scan storage adapters:
Normal Scanning: Scan storage devices. This type does not reset HBA ports.