Deployment KB: VPLEX: How to move one leg of a logging volume


   Article Number:     539564                                   Article Version: 3     Article Type:    How To 




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This article explains how to move one leg of the logging volume to a different array for better redundancy, or for migrations requirements.    
    Use Case: This is usually required during storage array migrations and tech refresh where you will need to also migrate the logging volume Mirrors.   
    First you need to create a new storage volume on the new target array.   

  •         The size of the new storage volume must be the same size or larger than the size of the old component (leg) of the logging volume you want to move.     
  •         By default the logging volume consists of components, these components are storage volumes that could be provisioned from the same array, or two different arrays.     
    Procedure to move just one leg of the logging volume to another array:    
    1. Identify the logging volume:   
      VPlexcli:/> cd clusters/cluster-1/system-volumes         
          VPlexcli:/clusters/cluster-1/system-volumes> ll         
          Name                                  Volume Type     Operational  Health  Active  Ready  Geometry  Component  Block     Block  Capacity  Slots         
          ------------------------------          --------------             Status       State   ------  -----          --------        Count        Count       Size       --------  -----         
          ------------------------------          --------------           -----------        ------  ------   -----          --------         ---------  --------         -----        --------  -----         
          Cluster1_logvol1_vol            logging-volume         ok               ok      -       -                 raid-1           2        2621440   4K           10G       -         
          c1meta                                  meta-volume            ok               ok      true    true          raid-1           2          26214144  4K     100G      64000         
          c1meta_backup_Nov02_230017  meta-volume     ok              ok      false   true          raid-1          1          26214144  4K     100G      64000         
          c1meta_backup_Nov03_230022  meta-volume     ok              ok      false   true          raid-1          1          26214144  4K     100G      6400
    2. List the logging volume components (legs) using the "show-use-hierarchy" cli command,   
      VPlexcli:/clusters/cluster-1/system-volumes> show-use-hierarchy Cluster1_logvol1_vol         
          logging-volume: Cluster1_logvol1_vol (10G, raid-1, cluster-1)         
            extent: extent_Cluster1_logvol_1_1 (10G)         
              storage-volume: Cluster1_logvol_1 (10G)         
                logical-unit: VPD83T3:600601600xxxxxxxxxxxxxe2ee58e         
                  storage-array: EMC-CLARiiON-CKMXXXXXXXX208         
            extent: extent_R_Rental_VPLEX1_Logging_Crossconnect_1 (10G)         
              storage-volume: R_Rental_VPLEX1_Logging_Crossconnect (40G)         
                logical-unit: VPD83T3:600601xxxxxxxxxxxxx6380cc8         
                  storage-array: EMC-CLARiiON-CKMXXXXXXXX247
    3. Specify the Slot Number of the mirror leg to detach:   
      VPlexcli:/clusters/cluster-1/system-volumes> ll Cluster1_logvol1_vol/components         
          Name                                                                                    Slot    Type    Operational     Health    Capacity         
          ----------------------------------------------------- ---------------------  Number --------    Status            State         
          ----------------------------------------------------- ------- ------ ----------------- -------         
          extent_Cluster1_logvol_1_1                                                         extent        ok                  ok         10G         
          extent_R_Rental_VPLEX1_Logging_Crossconnect_1           1       extent       ok                  ok         10G
    4. Detach the leg of the logging volume that is to be moved to a different array:   
    VPlexcli:/clusters/cluster-1/system-volumes> logging-volume detach-mirror --logging-volume Cluster1_logvol1_vol/ --slot 0   
    5.  Add new mirror (leg) from the different array to the logging volume:   
      VPlexcli:/clusters/cluster-1/system-volumes> logging-volume add-mirror --logging-volume Cluster1_logvol1_vol --mirror extent_Unity207_VLPEX2_Cluster2_logvol_1_1   
    6. Monitor the rebuild status   
        Once the new leg has been attached to the logging volume a rebuild will take place. You can monitor   
        the status of the rebuild so you will know when the rebuild is complete using the "rebuild status"   
      VPlexcli:/clusters/cluster-1/system-volumes> rebuild status   
    For more details about commands and examples look at VPLEX CLI Reference Guide for the version of GeoSynchrony running on the VPLEX.   






The procedure discussed in this article does not move the total logging volume, if you would like to move the total logging volume please refer to KBA 494898, "VPLEX: How to Move an entire logging volume", Where the procedure talked to in the KBA, to move the 'total' logging volume, is found on Solve Desktop or Online as follows, VPlex -> Administration -> Manage -> Move a logging volume   
    There is also a procedure you can get from SolVe Desktop/Online for "migrating data from old array to new array",   
    VPLEX > Administration > Manage >    
    Note: By default the logging volume consists of components, these components are storage volumes that could be provisioned from the same array, or two different arrays.   
    For redundancy we recommend to store the logging volume components on two different back-end arrays. This way should one array a leg is on have issues the leg on the other array will still be available.   
    You might need to do a data migration from one of the storage arrays to another array. In that case you do not have to totally move the logging volume, you can follow the above procedure to move the attached leg under one storage array to another storage array, while keeping the second leg attached to its own storage array.