Recommended fabric-attached MetroCluster configuration with array LUNs
When configuring a fabric-attached MetroCluster configuration with Data ONTAP systems and storage arrays, you should follow the best practice recommendations for how to connect the hardware components. The Interoperability Matrix at support.netapp.com contains information about the hardware components that are supported for a MetroCluster configuration using array LUNs without a PVR.
The following illustration shows the components and best practice configuration of a fabric-attached MetroCluster configuration that uses array LUNs from storage arrays. The fabric-attached MetroCluster configuration shown provides the same single-point-of-failure protections that are available for all mirrored HA pairs.
The following sections describe the connections for the fabric-attached MetroCluster configuration in the previous illustration.
Interconnections on Data ONTAP systems
The Data ONTAP systems in the sample MetroCluster illustration are configured to be an HA pair. They are interconnected by connecting ports A and B on each system's FC-VI adapter to alternate switch fabrics.
|Data ONTAP system||Switch||Fabric|
|vs1: Port A
vs1: Port B
|Switch 2, Port 12
Switch 1, port 2
|vs2: Port A
vs2: Port B
|Switch 4, port 17
Switch 3, port 7
If your Data ONTAP systems are dual-enclosure systems with two controllers in the same chassis (such as a 32xx system), you connect the top controller in one system to the top controller in the other system through the fabric. You connect the bottom controllers between the fabric in the same way. These two separate connections result in two separate fabric-attached MetroCluster configurations.
The following illustration shows the connections of the controllers to the switch fabric for dual-enclosure systems with two controllers in the same chassis. Controller A and Controller C form one MetroCluster configuration. Controller B and Controller D form the second MetroCluster configuration:
Inter-Switch Link connections (ISLs)
Fabric-attached MetroCluster configurations use a switched fabric to connect the local half of the configuration to the remote half of the configuration. The sample MetroCluster illustration shows the following:
- Switches 1 and 3 are connected to each other (Fabric 1).
The first fabric in the MetroCluster configuration begins from Switch 1 on Site A (local) and is completed by connecting the ISL cable to the first switch on Site B (remote)—Switch 3.
- Switches 2 and 4 are also connected (Fabric 2).
The second fabric is created using Switch 2 on Site A (local), connected through a second ISL cable, to the second switch on Site B (remote)—Switch 4.
The following table lists the ISLs in this configuration:
|Port 5 on switch 1||Port 10 on switch 3||Fabric 1|
|Port 14 on switch 2||Port 19 on switch 4||Fabric 2|
Data ONTAP system-to-switch connections
The best practice connections in the recommended MetroCluster illustration eliminate a single point of failure in the following ways:
- FC initiator ports on the same FC controller chip (for example, port 0a and 0b) connect to alternate fabrics.
- Multiple paths and zones ensure that FC initiator ports on the same controller chips access the array LUN from different Data ONTAP systems and switch fabrics.
The following table lists the connections from the Data ONTAP system to the switch:
|Data ONTAP system and FC initiator port||Switch|
|vs1: FC port 0a||Switch 1: Port 1|
|vs1: FC port 0b||Switch 2: Port 11|
|vs1: FC port 0c||Switch 1: Port 3|
|vs1: FC port 0d||Switch 2: Port 13|
|vs2: FC port 0a||Switch 3: Port 6|
|vs2: FC port 0b||Switch 4: Port 16|
|vs2: FC port 0c||Switch 3: Port 8|
|vs2: FC port 0d||Switch 4: Port 18|
Storage array-to-switch connections
Best practice connections from the storage array to the switch are as follows:
- Ports 1A and 2A on each storage array connect to alternate fabrics.
- Ports 1B and 2B on each storage array connect to alternate fabrics.
- Data ONTAP systems are configured to access any array LUN on two storage array paths (1A and 2A or 1B and 2B).
|Storage array port||Switch||Fabric|
|Array 1: Port 1A||Switch 1: Port 4||1|
|Array 1: Port 2A||Switch 2: Port 15||2|
|Array 1: Port 1B||Switch 1: Port 6||1|
|Array 1: Port 2B||Switch 2: Port 16||2|
|Array 2: Port 1A||Switch 3: Port 9||1|
|Array 2: Port 2A||Switch 4: Port 20||2|
|Array 2:Port 1B||Switch 3: Port 11||1|
|Array 2:Port 2B||Switch 4: Port 21||2|