Cisco ASR 9000 Series Aggregation Services Router System Management Configuration Guide, Release 4.0
Configuring Disk Mirroring on the Cisco ASR 9000 Series Router
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Configuring Disk Mirroring on the Cisco ASR 9000 Series Router

Configuring Disk Mirroring on the Cisco ASR 9000 Series Router

This module describes the process to configure disk mirroring in Cisco IOS XR software.

For complete descriptions of the commands listed in this module, see Related Documents. To locate documentation for other commands that might appear in the course of performing a configuration task, search online in Cisco ASR 9000 Series Aggregation Services Router Commands Master List.

Table 1 Feature History for Disk Mirroring for Cisco IOS XR Software

Release

Modification

Release 3.7.2

Disk mirroring was introduced.

This module contains the following topics:

Disk Mirroring Prerequisites

Before enabling disk mirroring, the following conditions must be met:

  • You must be in a user group associated with a task group that includes the proper task IDs. The command reference guides include the task IDs required for each command. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
  • The secondary storage device specified for the mirroring must be installed in the same node as the primary boot device. The supported storage devices are disk0: and disk1:.
  • The secondary storage device must be the same size or larger than the designated primary storage device.
  • The secondary storage device must be partitioned.

Note


The primary partition on the secondary storage device must be large enough to contain all data on the primary boot device. This can be an issue if the primary boot device has not yet been partitioned. For example, in the situation where both the primary boot device and the secondary storage device are 1 GB in size, the primary boot device contains 950 MB of data, and the secondary storage device is already partitioned to 800 MB in the primary partition and 200 MB in the secondary partition. In such a case, the 950 MB of data from the primary boot device does not fit on the secondary storage device because of the partition. Such a configuration is rejected and an error is displayed. You need to replace the secondary storage device with a higher capacity device. For information about disk partition sizes, see Related Topics.



Note


Although compactflash: can be used as the secondary device on a Performance Route Processor (PRP–2), there is an issue with the ROM Monitor not being able to boot the minimum boot image (MBI) from the secondary device if the device is not disk0: or disk1:. In such a situation, you would need to go into ROMMON mode and boot the PRP-2 manually using the MBI on the compactflash:.


Information About Disk Mirroring

The route switch processor (RSP) card has a primary storage device that is used to store installation packages and configuration files. This primary storage device is referred to as the primary boot device and is essential for booting the RSP and its normal operation.

Disk mirroring replicates the critical data on the primary boot device onto another storage device on the same RSP, henceforth referred to as the secondary device. If the primary boot device fails, applications continue to be serviced transparently by the secondary device, thereby avoiding a switchover to the standby RSP. The failed primary storage device can be replaced or repaired without disruption of service.

Disk mirroring should only mirror critical data on the primary boot device onto a secondary storage device and not any noncritical data such as logging data. To separate critical data from noncritical data, the disk devices need to be partitioned. Disk0: is partitioned to disk0: and disk0a:; disk1: is partitioned to disk1: and disk1a:. Disk0: and disk1: are used for critical data, whereas disk0a: and disk1a: are used for logging data and other noncritical data. Before you can configure disk mirroring on the RSP, you must have partitioned the secondary storage device. The sizes of disk partitions are related to the total disk size, and are provided in Table 1.

Table 2  Size of Disk Partitions in Relation to Size of Disk

Size of Disk

Primary Partition Percentage

Secondary Partition Percentage

less than 900 MB

Partitioning not supported

Partitioning not supported

900 MB to 1.5 GB

80%

20%

1.5 GB to 3 GB

60%

40%

more than 3 GB

50%

50%

How to Enable Disk Mirroring

The tasks in this section describe how to enable and manage disk mirroring.

Enabling Disk Mirroring

Complete the following instructions to enable disk mirroring. After disk mirroring is configured, if there is a fault on the primary boot drive or it cannot be accessed for any reason, control is automatically transferred to the secondary storage device.

SUMMARY STEPS

    1.    format secondary-device partition [ location node-id ]

    2.    Remove any noncritical data from the primary boot device.

    3.    configure

    4.    mirror location node-id Primary-device Secondary-device

    5.    Use one of these commands:

    • end
    • commit

    6.    show mirror [ location node-id ]

    7.    mirror verify location node-id


DETAILED STEPS
      Command or Action Purpose
    Step 1 format secondary-device partition [ location node-id ]


    Example:
    RP/0/RSP0/CPU0:router# format disk1: partition
    
     

    Partitions the secondary storage device into two partitions.

    • If the device is already partitioned, you do not need to perform this step.
     
    Step 2 Remove any noncritical data from the primary boot device.  

    The primary boot device should contain installation packages and configuration files only. Log files can be copied to the “a” partition of the secondary device, for example disk1a: .

     
    Step 3 configure


    Example:
    RP/0/RSP0/CPU0:router# configure
     

    Enters global configuration mode.

     
    Step 4 mirror location node-id Primary-device Secondary-device


    Example: RP/0/RSP0/CPU0:router(config)# mirror location 0/ rsp0/cpu0 disk0:disk1:  

    Enables disk mirroring of the primary-device to the secondary-device .

    If the primary boot device is not partitioned, the following occurs:

    • The contents of the primary device are replicated to the secondary device
    • Control of the mirroring server switches to the secondary storage device.
    • The primary device is partitioned.
    • Data is replicated back to the primary boot device.
     
    Step 5 Use one of these commands:
    • end
    • commit


    Example:
    RP/0/RSP0/CPU0:router(config)# end

    or

    RP/0/RSP0/CPU0:router(config)# commit
     

    Saves configuration changes.

    • When you issue the end command, the system prompts you to commit changes:
      Uncommitted changes found, commit them
      before exiting(yes/no/cancel)? [cancel]:
      
      • Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.
      • Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.
      • Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.
    • Use the commit command to save the configuration changes to the running configuration file, and remain within the configuration session.
     
    Step 6 show mirror [ location node-id ]


    Example: RP/0/RSP0/CPU0:router# show mirror location 0/ rsp0/cpu0  

    Displays disk mirroring information for an RSP node. It also provides the status of the synchronization between the primary and secondary devices.

     
    Step 7 mirror verify location node-id


    Example: RP/0/RSP0/CPU0:router# mirror verify location 0/ rsp0/cpu0  

    Verifies disk synchronization for disk mirroring on an RSP node.

     

    Replacing the Secondary Mirroring Device

    Follow this procedure if you need to replace the secondary boot device used in the disk mirroring process.

    SUMMARY STEPS

      1.    show mirror [location node-id]

      2.    mirror pause [location node-id]

      3.    show mirror [location node-id]

      4.    unmount secondary-device [location node-id]

      5.    Remove the device and insert a new device.

      6.    format secondary-device partition [location node-id]

      7.    show media [location node-id]

      8.    mirror resume [location node-id]

      9.    show mirror [location node-id]


    DETAILED STEPS
        Command or Action Purpose
      Step 1 show mirror [location node-id]


      Example:
      RP/0/RSP0/CPU0:router# show mirror
      
       

      Verifies that mirroring is active. In the output, the Current Mirroring State should be redundant.

       
      Step 2 mirror pause [location node-id]


      Example:
      RP/0/RSP0/CPU0:router# mirror pause
      
       

      Temporarily pauses disk mirroring.

       
      Step 3 show mirror [location node-id]


      Example:
      RP/0/RSP0/CPU0:router# show mirror
      
       

      Verifies that mirroring has paused. In the output, the Current Mirroring State should be paused.

       
      Step 4 unmount secondary-device [location node-id]


      Example:
      RP/0/RSP0/CPU0:router# unmount disk1: 
       

      Unmounts the secondary device.

       
      Step 5 Remove the device and insert a new device.   
      Step 6 format secondary-device partition [location node-id]


      Example:
      RP/0/RSP0/CPU0:router# format disk1: partition
      
       

      Formats the device.

       
      Step 7 show media [location node-id]


      Example:
      RP/0/RSP0/CPU0:router# show media
      
       

      Verifies that the device is formatted. The output should display the device that you formatted.

       
      Step 8 mirror resume [location node-id]


      Example:
      RP/0/RSP0/CPU0:router# mirror resume
      
       

      Resumes mirroring.

       
      Step 9 show mirror [location node-id]


      Example:
      RP/0/RSP0/CPU0:router# show mirror
      
       

      Verifies that mirroring has restarted. In the output, the Current Mirroring State should be Syncing.

      It can take 15 to 30 minutes for the mirroring process to complete. The exact time depends on the number of packages or files on the boot device. When the mirroring is complete, the Current Mirroring State should be Redundant.

       

      Replacing the Primary Mirroring Device

      In the event that your primary boot disk is defective and you need to replace it while disk mirroring is enabled, perform this task.

      SUMMARY STEPS

        1.    show mirror [location node-id]

        2.    configure

        3.    mirror location node-id Primary-device Secondary-device

        4.    Use one of these commands:

        • end
        • commit

        5.    show mirror [location node-id]

        6.    mirror pause [location node-id]

        7.    show mirror

        8.    unmount secondary-device [location node-id]

        9.    Remove the device and insert a new device.

        10.    show media [location node-id]

        11.    (Optional) format secondary-device partition [location node-id]

        12.    mirror resume [location node-id]

        13.    show mirror [location node-id]

        14.    configure

        15.    mirror location node-id Primary-device Secondary-device

        16.    show mirror [location node-id]


      DETAILED STEPS
          Command or Action Purpose
        Step 1 show mirror [location node-id]


        Example:
        RP/0/RSP0/CPU0:router# show mirror
        
         

        Verifies that mirroring is in the redundant state. In the output, the Current Mirroring State should be redundant. If mirroring is not in the redundant state, you cannot proceed with the procedure. You must wait until mirroring is in the redundant state.

         
        Step 2 configure


        Example:
        RP/0/RSP0/CPU0:router# configure
         

        Enters global configuration mode.

         
        Step 3 mirror location node-id Primary-device Secondary-device


        Example:
        RP/0/RSP0/CPU0:router(config)# mirror location 0/
        
        
        RSP0
        
        
        /CPU0 disk1:disk0:
        
         

        Swaps the device roles such that the primary mirroring device now becomes the secondary device and the secondary mirroring device becomes the primary device.

         
        Step 4 Use one of these commands:
        • end
        • commit


        Example:
        RP/0/RSP0/CPU0:router(config)# end

        or

        RP/0/RSP0/CPU0:router(config)# commit
         

        Saves configuration changes.

        • When you issue the end command, the system prompts you to commit changes:
          Uncommitted changes found, commit them
          before exiting(yes/no/cancel)? [cancel]:
          
          • Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.
          • Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.
          • Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.
        • Use the commit command to save the configuration changes to the running configuration file, and remain within the configuration session.
         
        Step 5 show mirror [location node-id]


        Example:
        RP/0/RSP0/CPU0:router# show mirror
        
         

        Verifies that the primary device is now the secondary device and vice versa. In the output, if disk0: was the primary disk that you want to replace, it should now be listed as the secondary device.

         
        Step 6 mirror pause [location node-id]


        Example:
        RP/0/RSP0/CPU0:router# mirror pause
        
         

        Temporarily pauses disk mirroring.

         
        Step 7 show mirror


        Example:
        RP/0/RSP0/CPU0:router# show mirror
        
         

        Verifies that mirroring has paused. In the output, the Current Mirroring State should be paused.

         
        Step 8 unmount secondary-device [location node-id]


        Example:
        RP/0/RSP0/CPU0:router# unmount disk1: 
         

        Unmounts the secondary device which is the device that you want to replace. Initially, this was the primary device.

         
        Step 9 Remove the device and insert a new device.   
        Step 10 show media [location node-id]


        Example:
        RP/0/RSP0/CPU0:router# show media
        
         

        Verifies that the new disk is partitioned. You should see that the new device is mounted. If the new device is not partitioned, format the device as indicated in the next step.

         
        Step 11 format secondary-device partition [location node-id]


        Example:
        RP/0/RSP0/CPU0:router# format disk1: partition
        
         
        (Optional)

        Formats the device. You only need to perform this step if the new device is not partitioned.

         
        Step 12 mirror resume [location node-id]


        Example:
        RP/0/RSP0/CPU0:router# mirror resume
        
         

        Resumes mirroring.

         
        Step 13 show mirror [location node-id]


        Example:
        RP/0/RSP0/CPU0:router# show mirror
        
         

        Verifies that mirroring has restarted. In the output, the Current Mirroring State should be Syncing.

        It can take 15 to 30 minutes for the mirroring process to complete. The exact time depends on the number of packages or files on the boot device. When the mirroring is complete, the Current Mirroring State should be Redundant.

         
        Step 14 configure


        Example:
        RP/0/RSP0/CPU0:router# configure
         

        Enters global configuration mode.

         
        Step 15 mirror location node-id Primary-device Secondary-device


        Example:
        RP/0/RSP0/CPU0:router(config)# mirror location 0/
        
        
        RSP0
        
        
        /CPU0 disk0:disk1:
        
         

        Swaps the device roles back so that the newly inserted device becomes the primary device.

         
        Step 16 show mirror [location node-id]


        Example:
        RP/0/RSP0/CPU0:router# show mirror
        
         

        Verifies that the new device is now the primary device.

         

        Configuration Examples for Enabling Disk Mirroring

        Enabling Disk Mirroring: Example

        In the following example, disk mirroring is enabled on a router:

        format disk1: partition 
          
        This operation will destroy all data on "disk1:" and partition device. 
        Continue? [confirm] y
          
        Device partition disk1: is now formated and is available for use. 
          
        configure
          mirror location 0/0/cpu0 disk0:disk1:
          commit
          

        show mirror Command Output: Example

        RP/0/RSP0/CPU0:router(admin)# show mirror location all
        
        Tue Dec  7 13:02:26.520 PST
        
        Mirror Information for 0/RSP0/CPU0.
        ========================================================
         Mirroring Enabled
           Configured Primary:         disk0:
           Configured Secondary:       disk1:
        
         Current Mirroring State:      Redundant
           Current Physical Primary:   disk0:
           Current Physical Secondary: disk1:
        
         Mirroring Logical Device:     disk0:
         Mirroring Logical Device2:    disk1:
        
         Physical Device     State       Flags
        --------------------------------------------------------
          disk0:           Available     Enabled 
          disk1:           Available     Enabled 
          compactflash:    Available     
          (null)           Available     
          disk0a:          Available     
          disk1a:          Available     
          compactflasha:   Not Present   
          harddisk:        Available     
        
        Mirroring Rommon Variable
         BOOT_DEV_SEQ_CONF = disk0:;disk1:
         BOOT_DEV_SEQ_OPER = disk0:;disk1:
         MIRROR_ENABLE = Y
          

        mirror verify Command Output: Example

        RP/0/RSP0/CPU0:router# mirror verify
          
        Mirror Verify Information for 0/0/CPU0.
        ========================================================
          Primary device and secondary device are fully synchronized.
           

        Additional References

        The following sections provide references related to disk mirroring configuration.

        Related Documents

        Related Topic

        Document Title

        Initial system bootup and configuration information for a router using the Cisco IOS XR software

        Cisco ASR 9000 Series Aggregation Services Router Getting Started Guide

        Information about user groups and task IDs

        Configuring AAA Services on the Cisco ASR 9000 Series Router module of Cisco ASR 9000 Series Aggregation Services Router System Security Configuration Guide

        Cisco IOS XR command master list

        Cisco ASR 9000 Series Aggregation Services Router Commands Master List

        Cisco IOS XR boot commands

        Boot Commands on the Cisco ASR 9000 Series Router module of Cisco ASR 9000 Series Aggregation Services Router System Management Command Reference

        Standards

        Standards

        Title

        No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

        MIBs

        MIBs

        MIBs Link

        To locate and download MIBs using Cisco IOS XR software, use the Cisco MIB Locator found at the following URL and choose a platform under the Cisco Access Products menu: http:/​/​cisco.com/​public/​sw-center/​netmgmt/​cmtk/​mibs.shtml

        RFCs

        RFCs

        Title

        No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

        Technical Assistance

        Description

        Link

        The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

        http:/​/​www.cisco.com/​cisco/​web/​support/​index.html