Modifying VLAN for priority flow control

You can change Virtual Local Area Network (VLAN) settings to separate network traffic for Ethernet transport.

The system supports VLAN configuration for system, host attachment, storage virtualization, and IP replication traffic. VLAN can be used with priority flow control (PFC) which is a mechanism that is enabled on switches and adapter ports in the network. PFC creates different classes for all types of traffic that improves network performance during times of congestion. To ensure that PFC operates as expected, the network and its components must be configured correctly. For example, if a single port is used for multiple types of traffic (node-to-node communications, host attachment, and storage ) then the performance of these traffic types can be affected. The system supports setting system-wide PFC-setting on traffic for node-to-node communications, host attachment traffic, and storage virtualization traffic. PFC capabilities are not supported on IP replication traffic. VLAN tags must be assigned to IP versions for which you want to use PFC capabilities.

Modifying VLAN for nodes

For systems that support node-to-node connections that use iSCSI extensions over RDMA (iSER)-based protocols, such as RDMA over Converged Ethernet (RoCE) or Internet Wide Area RDMA (iWARP), VLAN settings must be configured to prevent any connection issues. To use these protocols, the system requires that a 25 Gbps Ethernet adapter is installed on each node. VLAN tags need to be the same on each node that connects using these protocols. If VLAN tags are not the same between nodes, a Disconnected status with error data of VLAN ID Mismatch displays on the Ethernet Connectivity page in the management GUI. To fix this error, you need to access the service assistant GUI by entering the node's service IP address into a supported web browser.
Note: These instructions assume all hardware installation and system configuration is complete. If you cannot access a node, ensure that all installation and configuration steps are correct before proceeding.
  1. In a supported browser, enter the service IP address for the node.
  2. In the service assistant GUI, select Change Node IP.
  3. Select the node from the drop down. The service assistant GUI displays all configured port IP addresses for the selected node.
  4. Verify the VLAN settings are the same for each configured IP address. If VLAN IDs do not match, select the port IP address and select Modify.
  5. In the VLAN field, enter the correct VLAN ID for the port IP address.
  6. Click Save.
  7. After configuring VLAN settings for the nodes, you can configure PFC for the node-to-node traffic.
    Note: If you are sharing the same port for different types of traffic then PFC and Enhanced Transmission Selection (ETS) settings must be configured.

Configuring VLAN for host attachment

When you configure VLAN tagging for host connections, follow these guidelines:
  • To configure VLAN tagging without disrupting I/O from hosts, all hosts need multiple ports and multipath drivers. In addition, each host must be configured with multiple sessions to each port on the system.
  • Each session needs to be stopped one at a time to ensure that I/O can continue on alternative paths to the system.

If you are running previous versions of the system, configuring VLAN tags for host sessions is a disruptive process.

Complete these steps to configure VLAN tags on existing host sessions:
  1. On the hosts, configure VLAN on the host ports that are used for iSCSI or iSER connections. Consult the appropriate host documentation to complete this step.
  2. On all intervening switches, configure the switches with the VLAN tags per port connectivity. Consult the appropriate switch documentation to complete this step.
  3. Verify that the port on which you are configuring VLAN tags is used for host attachment. In the management GUI, select Settings > Network > Ethernet Ports. Ensure that Yes is displayed in the host attach column for the selected port. If No is displayed, right-click the port and select Modify iSCSI hosts and select Enabled.
  4. Configure ports on the system with appropriate VLAN tags by completing these steps:
    1. In the management GUI, select Settings > Network > Ethernet Ports.
    2. Right-click the port on which to configure VLAN and select Actions > Modify VLAN.
    3. On the Modify VLAN page, select to enable VLAN for IP connections.
    4. Enter the VLAN tag and select whether to use the same VLAN tag for the failover port. If the failover port does not have the same VLAN tag, a host can lose access to the volumes. To prevent a loss of access, select to use the same VLAN tag for the failover port.
    5. Click Modify.
  5. After configuring VLAN settings for host attachment, ensure that you set the priority flow control (PFC) setting for the host attachment traffic.
    Note: If you are sharing the same port for different types of traffic then PFC and Enhanced Transmission Selection (ETS) settings must be configured.

Configuring VLAN for storage virtualization

VLAN tagging of the IP addresses configured for external storage systems is supported. For the systems and external storage systems to access each other, the same VLAN ID must be configured for ports on nodes on the system and the ports on the external storage system. In addition, VLAN settings must be configured on the Ethernet network to prevent any connection issues. When more than two ports are available, configure different ports for iSCSI hosts, remote-copy, and storage systems.

Complete these steps to configure VLAN tags on storage systems:
  1. On the storage systems, configure VLAN on the ports that are used for Ethernet connections. Consult the appropriate storage documentation to complete this step.
  2. On all intervening switches, configure the switches with the VLAN tags per port connectivity. Consult the appropriate switch documentation to complete this step.
  3. Verify that the port on which you are configuring VLAN tags is used for storage system attachment. In the management GUI, select Settings > Network > Ethernet Ports. Ensure that Enabled is displayed in the Storage Port column for the selected port. If Disabled is displayed, right-click the port and select Modify Storage Ports to enable the port for iSCSI connections to storage systems.
  4. Configure ports on the system with appropriate VLAN tags by completing these steps:
    1. Right-click the node port that is configured for external storage connections and select Modify VLAN. Select to enable VLAN.
    2. Enter the VLAN tag and select whether to use the same VLAN tag for the failover port. If the failover port does not have the same VLAN tag, a host can lose access to the volumes. To prevent a loss of access, select to use the same VLAN tag for the failover port.
    3. Click Modify.
  5. After configuring VLAN settings for storage virtualization, ensure that you set PFC settings for the system-to-storage traffic.
    Note: If you are sharing the same port for different types of traffic then PFC and Enhanced Transmission Selection (ETS) settings must be configured.
    For more information on PFC settings for storage virtualization, see Configuring priority flow control.