Remote-copy port groups

Remote-copy port groups are unique to IP partnerships, and are the local and remote IP addresses accessible to each other through an IP partnership. A remote-copy port group must contain at least one IP address in the local system and one IP address in the remote system. You must configure ports and assign to them a remote-copy port group number before establishing the IP partnership.

A remote-copy port group is designated by a number in the range 0 - 2 inclusive that identifies a set of IP addresses. These port groups are defined as shown in the following list:

The system selects one pair of IP addresses within port groups 1 and 2, one address on each system, and opens a remote copy connection between them.

Note: Each IP address can be shared for iSCSI host attachment and remote copy functions. Therefore, the appropriate settings must be applied to each IP address.

VLAN tagging of the IP addresses configured for remote copy is supported. If VLAN is to be configured, ports in the same remote copy group must be on the same VLAN on both systems.

Determining which ports are used and unused

After an IP partnership is created, you can enter the svcinfo lsportip command from the command line to determine the subset of ports that are actively being used for the remote copy operation. This information is helpful when you have a single intersystem link and have configured another IP port within the same remote-copy port group. This information is also helpful when two I/O groups are configured in an IP partnership with a remote system. This information gives you an understanding of which ports are actively participating in IP partnership, and which can act as failover ports.

In the lsportip output, the remote_copy_status field (or remote_copy_status6 for IPv6 ports) indicates the status of the port.
used
The port was configured for use in the IP partnership and was selected by the system for sending and receiving remote copy data.
unused
The port was configured for use in the IP partnership, but is not currently selected for sending and receiving remote copy data.
Blank
The port was not configured for use by the IP partnership.

The following example shows the output of the lsportip command.

lsportip
id	node_id node_name IP_address mask gateway IP_address_6 prefix_6 gateway_6 MAC duplex state speed failover link_state host remote_copy host_6 remote_copy_6
remote_copy_status remote_copy_status_6
1	1 node1 9.71.48.64 255.255.254.0 9.71.48.1 e4:1f:13:75:8d:d8 Full configured 100Mb/s no active yes 0 0
1	1 node1 e4:1f:13:75:8d:d8 Full configured 100Mb/s yes active 0 0
2	1 node1 10.10.12.12 255.255.255.0 10.10.12.1 e4:1f:13:75:8d:d7 Full configured 1Gb/s no active no 0 0
2	1 node1 e4:1f:13:75:8d:d7 Full configured 1Gb/s yes active 0 0
3	1 node1 10.10.13.12 255.255.255.0 10.10.13.1 00:00:c9:cd:0b:8e Full configured 10Gb/s no active no 1 0 used
3	1 node1 00:00:c9:cd:0b:8e Full unconfigured 10Gb/s yes active 0 0
4	1 node1 00:00:c9:cd:0b:90 unconfigured no inactive 0 0
4	1 node1 00:00:c9:cd:0b:90 configured yes inactive 0 0
1	2 node2 9.71.48.122 255.255.254.0 9.71.48.1 e4:1f:13:75:5d:24 Full configured 100Mb/s no active yes 0 0
1	2 node2 e4:1f:13:75:5d:24 Full configured 100Mb/s yes active 0 0
2	2 node2 10.10.22.12 255.255.255.0 10.10.22.1 e4:1f:13:75:5d:23 Full configured 1Gb/s no active no 0 0
2	2 node2 e4:1f:13:75:5d:23 Full configured 1Gb/s yes active 0 0
3	2 node2 00:00:c9:d2:66:f2 unconfigured no inactive 0 0
3	2 node2 00:00:c9:d2:66:f2 configured yes inactive 0 0
4	2 node2 10.10.24.12 255.255.255.0 10.10.24.1 00:00:c9:d2:66:f4 Full configured 10Gb/s no active no 0 0
4	2 node2 00:00:c9:d2:66:f4 Full unconfigured 10Gb/s yes active 0 0

This information can also be obtained by selecting Settings -> Network -> Ethernet Ports in the management GUI. For more information about how to configure remote-copy port groups, see Configuring IP partnerships.

Failover operations within and between port groups

Within one remote-copy port group, only one port from each system is selected for sending and receiving remote copy data at any one time. Therefore, on each system, at most one port for each remote-copy port group is reported as "used".

If the IP partnership becomes unable to continue over an IP port, the system fails over to another port within that remote-copy port group. This situation might occur one of the following reasons: the switch to which it is connected fails, the node canister goes offline, or the cable that is connected to the port is unplugged.

For the IP partnership to continue during a failover, multiple ports must be configured within the remote-copy port group. If only one link is configured between the two systems, configure two ports (one per node) within the remote-copy port group. You can configure these two ports on two nodes within the same I/O group or within separate I/O groups. Configurations 4, 5, and 6 in IP partnership requirements are the supported dual-link configurations.

While failover is in progress, there are no connections in that remote-copy port group between the two systems in the IP partnership for a short time. Typically, failover completes within 30 seconds to 1 minute. If the systems are configured with two remote-copy port groups, the failover process within each port group continues independently of each other.

Note: In this scenario, make sure that any node in either system has at most one port that is configured for IP partnership.

The disadvantage of configuring only one link between two systems is that, during a failover, a discovery is initiated. When the discovery succeeds, the IP partnership is reestablished; as a result, the relationships might stop and a manual restart might be required. To configure two intersystem links, you must configure two remote-copy port groups.

When a node fails in this scenario, the IP partnership can continue over the other link until the node failure is rectified. Failback then happens when both links are again active and available to the IP partnership. The discovery is triggered so that the active IP partnership data path is made available from the new IP address. In a two-node system, or if there is more than one I/O Group and the node in the other I/O group has IP ports that are pre-configured within the remote-copy port group, the discovery is triggered so that the active IP partnership data path is made available from the new IP address.