Cisco SN 5420 Storage Router Software Configuration Guide, Release�2.1
Chapter 9 - Configuring a Storage Router Cluster
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Configuring a Storage Router Cluster

Table Of Contents

Configuring a Storage Router Cluster

Prerequisite Tasks

Adding Storage Routers to a Cluster

Adding an Unconfigured Storage Router

Adding a Minimally Configured Storage Router

Adding Completely Configured Storage Routers

Changing Clusters

Temporarily Removing a Cluster Node


Configuring a Storage Router Cluster


This chapter explains how to configure SN 5420 Storage Routers in a cluster to allow the storage routers to back each other up in case of failure. The following tasks are covered:

Prerequisite Tasks

Adding Storage Routers to a Cluster

Changing Clusters

Temporarily Removing a Cluster Node

Storage router clusters can be configured using CLI commands, as described in this chapter, or via the web-based GUI. To access the web-based GUI, point your browser to the storage router's management interface IP address. After logging on, click the Help link to access online help for the GUI.


Note Storage routers that are deployed for iSCSI SAN interconnect or for transparent SCSI routing cannot participate in a storage router cluster.


Prerequisite Tasks

Before performing any storage router cluster configuration tasks, make sure you have configured system parameters, including the HA interface, as described in "First-Time Configuration," or "Configuring System Parameters."

Adding Storage Routers to a Cluster

In most situations, you will completely configure a principal SN 5420 Storage Router (including all cluster-wide settings), and then add new, unconfigured storage routers or minimally configured storage routers to the cluster. A cluster can include a maximum of four storage routers.

The following storage router configuration settings are shared cluster-wide, and when configured on the first storage router in the cluster, will be shared with all other storage routers that join the cluster.

Access lists

Cluster name

SCSI routing instances

VLAN information (VID, VTP mode, domain name, etc.)


Note A minimally configured storage router is one in which the management IP address, system name, and optional network management interfaces have been configured. Other system information, such as HA IP address, administrator and monitor passwords, may also have been configured. A minimally configured storage router, however, must not have had any cluster-wide settings configured.


Adding an Unconfigured Storage Router

To add a new, unconfigured storage router to an existing cluster, perform the following steps:


Step 1 Respond to the prompts from the storage router initial system configuration script. This script configures the following settings:

Management IP address

System name

HA configuration mode

Cluster name

HA IP address

When prompted to select HA configuration mode, choose clustered. When prompted for cluster name, enter the name of the existing cluster. At the end of the initial system configuration script, the storage router automatically reboots.

Step 2 When the storage router restarts, it communicates with other members of the cluster to obtain current cluster configuration information. Once the storage router is completely restarted, verify the new cluster configuration. Issue the show cluster command to verify the cluster name and confirm that the storage router is exchanging heartbeats with the other members of the cluster.

Step 3 To verify that all machines in the cluster include the same configuration, issue the following commands from the principal storage router in the cluster:

show accesslist all from bootconfig

show scsirouter all from bootconfig

show vlan

show vtp

Issue the same commands from the storage router just added to the cluster. The displays should be the same.

Step 4 Use the setup configuration wizard, CLI commands, or the GUI to complete storage router configuration. See "First-Time Configuration," or "Configuring System Parameters," for complete details.

Step 5 (Optional) Save any changes made to the configuration by issuing the appropriate save command with the bootconfig keyword, which updates the bootable configuration for the storage router and notifies all storage routers in the cluster of the configuration changes.

Step 6 (Optional) To divide the workload between the storage routers in the cluster, you can manually failover selected SCSI routing instances using the failover scsirouter command. For additional information about failing over SCSI routing instances, see the section "Controlling SCSI Routing Instances in a Cluster" in "Maintaining and Managing the Storage Router."


Adding a Minimally Configured Storage Router

To add a minimally configured storage router to an existing cluster, perform the following steps:


Step 1 Run the setup cluster configuration wizard.

When prompted to select HA configuration mode, choose clustered.

When prompted for cluster name, enter the name of the existing cluster.

When prompted to retain or delete scsirouter instances, enter delete. Deleting means that any existing SCSI routing instances will be deleted from this storage router. (Since this is a minimally configured storage router, there should be no SCSI routing instances to delete.)

Enter yes to confirm your changes. The storage router automatically reboots.

Step 2 When the storage router restarts, it communicates with other members of the cluster to obtain current cluster configuration information. Once the storage router is completely restarted, verify the new cluster configuration. Issue the show cluster command to verify the cluster name and confirm that the storage router is exchanging heartbeats with the other members of the cluster.

Step 3 To verify that all machines in the cluster include the same configuration, issue the following commands from the principal storage router in the cluster:

show accesslist all from bootconfig

show scsirouter all from bootconfig

show vlan

show vtp

Issue the same commands from the storage router just added to the cluster. The displays should be the same.

Step 4 Complete additional system configuration of the storage router just added to the cluster, as needed. For example:

Use the setup access configuration wizard to configure passwords for the storage router.

Use the setup netmgmt configuration wizard to configure the storage router for network management via SNMP.

Use the setup time configuration wizard to configure the storage router date and time, and optional NTP server information.

Use the CLI or GUI to configure AAA authentication. See "Configuring Authentication," for additional information.

Step 5 Save any changes to the configuration by issuing the appropriate save command with the bootconfig keyword, which updates the bootable configuration for the storage router and notifies all storage routers in the cluster of the configuration changes.

Step 6 (Optional) To divide the workload between the storage routers in the cluster, you can manually failover selected SCSI routing instances using the failover scsirouter command. For additional information about failing over SCSI routing instances, see the section "Controlling SCSI Routing Instances in a Cluster" in "Maintaining and Managing the Storage Router."


Adding Completely Configured Storage Routers

In some cases you may prefer to completely configure all storage routers (including SCSI routing instances and access lists) as standalone systems before joining them into a cluster.

The following example explains the steps required to create a cluster named Cluster1, composed of two storage routers named SN5420Sys1 and SN5420Sys2. This example assumes that both storage routers are fully configured with SCSI routing instances and access lists. (See "Configuring SCSI Routing," for details.) Use the scsirouter primary command to assign a preferred storage router to any or all of the SCSI routing instances, if desired.


Note A cluster supports up to 12 active SCSI routing instances.


To create a cluster from fully configured storage routers, perform the following steps:


Step 1 Use the setup cluster configuration wizard to define SN5420Sys1 as a member of the cluster Cluster1. When prompted, enter retain to keep the access list and SCSI routing instance information already defined.

Step 2 Use the show cluster command to verify the cluster name after SN5420Sys1 reboots. Verify that all instances and access lists are still available, using show scsirouter and show accesslist commands.

Step 3 (Optional) On SN5420Sys2, save any access list information that you want to make available in the cluster to a file, using the save accesslist command. For example, to save all access lists to a file named SN5420Sys2_AccessLists.xml:

save accesslist all SN5420Sys2_AccessLists.xml

Step 4 (Optional) Because access lists can only be manipulated from the first storage router in a cluster, the saved configuration file from SN5420Sys2 must be made available to SN5420Sys1. See "Maintaining and Managing the Storage Router," for information on managing storage router saved configuration files using either the copy savedconfig command or FTP.

Step 5 Join SN5420Sys2 to the new cluster named Cluster1, using the setup cluster configuration wizard. When prompted, enter retain to share the existing SCSI routing instances across the cluster.

Step 6 Use the show cluster command to verify the cluster name after SN5420Sys2 reboots. Verify that the defined SCSI routing instances were retained, using show scsirouter command.

Step 7 (Optional) Restore any access lists saved in Step 3 using the restore accesslist from command. Access lists can only be manipulated from the first storage router in a cluster, so these commands must be issued from the system SN5420Sys1.

Step 8 (Optional) Save all configuration information on system SN5420Sys1 by issuing a save all bootconfig command, which updates the bootable configuration of all storage routers in the cluster.

Step 9 Verify that all SCSI routing instances are active using the show scsirouter stats command on both storage routers.


To add additional fully-configured storage routers to the existing cluster (for example, Cluster1), follow Steps 3 through 9. Perform Steps 3, 4, 5, and 6 on the storage router being added to the cluster (for example, SN5420Sys3). Perform Steps 7, 8, and 9 as described.

Changing Clusters

In some situations, you may need to move a storage router from one cluster to another cluster. Moving a fully configured storage router from one cluster to another is more complex than simply adding a storage router to a cluster. Advanced planning is required.

To successfully move a storage router from one cluster to another, perform the following steps:


Step 1 Verify that the storage router to be moved has the same hardware configuration as the other storage routers in the cluster you are planning to join. Each storage router in the cluster must have connectivity to the same hosts and storage devices. All management interfaces for the storage routers within a cluster must be on the same IP subnet, and all HA interfaces for the storage routers within a cluster must be on the same IP subnet. However, the management interfaces must be on a different IP network than the HA interfaces.

Step 2 Decide if you need to retain any SCSI routing instances defined on the storage router joining the cluster with the existing cluster data. Retaining data means all SCSI routing instances existing on the storage router joining the cluster will be added to those already defined for the cluster. If the existing instances are not retained, they are deleted.

Step 3 If you are going to retain data, determine if you have any duplicate SCSI routing instance names. When the storage router is added to the cluster, the data in the cluster will overwrite the existing data. You may prefer to change the configuration in the storage router before it joins the cluster to prevent this situation.

Step 4 If you are going to retain data, determine if you need to save existing access list information. Access lists are not retained. Any access lists on the storage router will be discarded when it joins the new cluster. You can save the access list information and then restore it to the cluster. Access list information can be restored before or after the storage router joins the cluster by transferring the saved configuration file to the first storage router in the cluster and performing the restore.

Step 5 Use the setup cluster configuration wizard to join the new cluster. Respond to the prompts to retain or delete configuration as required. The storage router will automatically reboot at the end of the configuration wizard.

Step 6 Perform any additional configuration that may be needed. You can fail over SCSI routing instances to this new cluster member to balance traffic load between all storage routers in the cluster.

Step 7 Use the save all command with the bootconfig keyword to copy and save the storage router configuration, thereby updating the cluster.


Temporarily Removing a Cluster Node

If a storage router requires hardware or software maintenance, you may want to remove it from the cluster on a temporary basis, but retain all cluster and node-specific configuration information.

To temporarily remove a storage router from a cluster and then return it to the cluster, perform the following steps:


Step 1 Fail over any SCSI routing instances that you want to continue running to other storage routers in the cluster using the failover command.

Step 2 Issue the setup cluster configuration wizard to temporarily remove the storage router from the cluster.

When prompted to select HA configuration mode, choose standalone.

When prompted for cluster name, allow the cluster name to default to the existing cluster.

When prompted to retain or delete scsirouter instances, enter retain to keep existing access lists and SCSI routing instances.

Enter yes to confirm your changes. The storage router automatically reboots.

Step 3 Issue the show cluster command to verify that the storage router is in standalone mode, and that no heartbeats are being exchanged with other cluster members.

Step 4 Perform the desired maintenance to the SN 5420.

Step 5 Once the maintenance is completed, use the setup cluster configuration wizard to return the storage router to the cluster.

When prompted to select HA configuration mode, choose clustered.

When prompted for cluster name, accept the default to rejoin the existing cluster.

When prompted to retain or delete scsirouter instances, choose delete to rejoin the cluster and assume the cluster's SCSI routing instance configurations. Choose retain if you want to merge the SCSI routing instance configurations on this storage router with those on the cluster.

Enter yes to confirm your changes. The storage router automatically reboots.

Step 6 After the storage router reboots, issue the show cluster command to verify that the storage router is in clustered mode and that heartbeats are being exchanged with other cluster members.

Step 7 Fail over any SCSI routing instances that you want to start running on this storage router from the other cluster members.