Specifications

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Cisco SN 5428-2 Storage Router Software Configuration Guide
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Chapter 10 Configuring a High Availability Cluster
Creating a Cluster
Guidelines for Configuring SCSI Routing Instances
When you configure SCSI routing instances to run in a high availability cluster, the following
operational guidelines apply:
• A cluster supports up to 12 active SCSI routing instances.
• If you map targets using WWPN, be sure to specify both the primary WWPN (the WWPN associated
with the storage resource as known to the primary node in the cluster) and the secondary WWPN
(the WWPN associated with the storage resource as known to the second node in the cluster).
• Each storage router in a cluster maintains and exchanges information about available resources.
Failover by eligibility is enabled by default; HA bases the decision to automatically fail over a SCSI
routing instance to another storage router in a cluster based on the Fibre Channel and other resources
available to that SCSI routing instance.
Failover occurs when:
– All mapped targets are unavailable or a critical resource for the SCSI routing instance is
unavailable, and some or all mapped targets would be available from another storage router in
the cluster. A critical resource can be a configured Gigabit Ethernet interface, a required Fibre
Channel interface, or an internal resource needed to run the SCSI routing instance.
– Some mapped targets are unavailable and all mapped targets are available on another storage
router in the cluster.
– All mapped targets are available, but another storage router in the cluster also has all targets
available and is designated at the primary for the SCSI routing instance.
– The storage router stops receiving heartbeats from another node within the cluster.
Note If you need more manual control over where a SCSI routing instance runs, you can turn off failover by
eligibility on a storage router. If a SCSI routing instance fails over to a storage router that is configured
with failover by eligibility turned off, it will continue running on that storage router unless there are no
mapped targets available or a critical resource is unavailable. Normal failover resumes when failover by
eligibility is turned back on for the storage router where the SCSI routing instance is running.
Creating a Cluster
A high availability cluster is composed of two SN 5428-2 Storage Routers (or one SN 5428-2 and one
SN 5428) that back each other up in case of failure. Storage routers in a cluster have connectivity to the
same hosts and storage systems, and are connected to each other through their management and HA
interfaces. Storage routers in a cluster must be running the same version of software.
The following configuration settings are shared cluster-wide, and when configured on the first storage
router in the cluster, will be shared with the other storage router that joins the cluster.
• AAA authentication
• Access lists
• Administrator mode and Monitor mode passwords
• Cluster name
• SCSI routing instances
• VLAN information (VID, VTP mode, domain name, etc.)