These RDMA-capable adapters must be installed in the same slots across all the nodes of the system. These installation requirements ensure that port identifiers are the same across all nodes in the system. 

GLYPH<SM590000> Ethernet cables between each node are connected correctly. 

GLYPH<SM590000> The protocol technology on the source and destination adapters is the same. 

GLYPH<SM590000> The local and remote IP addresses can be reached. 

GLYPH<SM590000> Each IP address for RDMA-capable Ethernet ports and their associated subnet masks are unique on each node. 

GLYPH<SM590000> Routers must not be placed between nodes that use RDMA-capable Ethernet ports for node-to-node communication. 

GLYPH<SM590000> The negotiated speeds on the local and remote adapters are the same. 

GLYPH<SM590000> The local and remote port virtual LAN identifiers are the same. Use virtual LAN to create physical separation of networks for unrelated systems, wherever possible. All the ports that are used for node-to node communication must be assigned with one VLAN ID, and ports that are used for host attachment must have a different VLAN ID. 

If you plan to use VLAN to create this separation, you must configure VLAN support on the all the Ethernet switches in your network before you define the RDMA-capable Ethernet ports on nodes in the system. On each switch in your network, set VLAN to Trunk mode and specify the VLAN ID for the RDMA-ports that will be in the same VLAN. 

In addition, if VLAN settings for a RDMA-capable Ethernet port need to be updated, these settings cannot be updated independently of other configuration settings. Before you update VLAN settings on specific RDMA-capable Ethernet ports, you must unconfigure the port, make any necessary changes to the switch configuration, then reconfigure RDMA-capable Ethernet ports on each of the nodes in the system. 

GLYPH<SM590000> A minimum of two dedicated RDMA-capable Ethernet ports are required for node-to-node communications to ensure best performance and reliability. These ports must be configured for inter-node traffic only, and must not be used for host attachment, virtualization of Ethernet-attached external storage, or IP replication traffic. 

GLYPH<SM590000> A maximum of four RDMA-capable Ethernet ports per node are allowed for node-to-node communications. 

## 4.8.5 Migrating with volume mirroring 

You can also use volume mirroring when you migration volume from existing storage to IBM SVC and Storwize V7000. As you can see in Figure 4-16 on page 165, you first need to attach existing storage to IBM SVC and Storwize V7000 by using a virtualization solution. 

In this case, you need some downtime to attach storage to IBM SVC and Storwize V7000. Next, attach mirrored volumes to hosts so that the host can recognize volumes same as existing ones. You can now restart applications. Volume mirroring is implemented with background after sync starts. 

