Follow these guidelines when you plan to configure a virtual
local area network (VLAN) for iSCSI-attached hosts.
- VLAN tagging is supported for iSCSI traffic. VLAN provides network
traffic separation at the layer 2 level for Ethernet transport.
- VLAN tagging by default is disabled for any IP address of a node
port. You can use the command-line interface (CLI) to optionally set
a VLAN ID for port Internet Protocols (IPs).
- To prevent connectivity issues when a VLAN ID is configured for
the IP addresses that are used for iSCSI host attachment, appropriate
VLAN settings on the Ethernet network and servers must also be properly
configured.
- A VLAN ID can be configured on system 1G Ethernet ports and 10G
Ethernet ports.
- A VLAN ID can be configured for IPv4 addresses and IPv6 addresses
of Ethernet ports.
- The same VLAN ID can be configured for all the Ethernet port IP
addresses, or a different VLAN ID can be configured on each Ethernet
port IP address.
- Setting VLAN tags for iSCSI host attachment sessions that are
already configured with a system that is running software before version 7.4.0 is a disruptive
process.
- To configure VLAN tags for existing host attachment sessions:
- Configure VLAN on host ports that are used for iSCSI connectivity.
- Configure all intervening switches with appropriate VLAN tags
according to port connectivity.
- Configure system ports with appropriate VLAN tags.
- If VLAN tagging needs to be done without disrupting I/Os from
hosts, the host should have multiple ports. Multipath drivers on hosts
must be correctly configured with multiple iSCSI sessions to each
system iSCSI port. Then, when you configure VLANs, iSCSI sessions
must be brought down one at a time so that I/Os can continue through
alternate paths to the system. Depending on switch connectivity, this
process might or might not be possible.
- To ensure reliable connectivity to storage during a node failure,
configure the same VLAN ID on the local and failover port on two nodes
of an I/O group.
- If different VLAN IDs are set for local and failover
port on two nodes of an I/O group, configure both VLAN IDs on the
Ethernet switch ports. This way, a failover of IP addresses from a
failing node to a surviving node succeeds. This setting is required
to avoid a loss of paths to storage during a node failure.
- After VLANs are configured, changes to the VLAN settings disrupt
iSCSI traffic to or from those Ethernet ports.
- A configuration with different VLANs on different ports but with
the same subnet on the ports is not supported.