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The following procedure describes how to perform the online data mobility process. 

  • The data mobility to the target InfiniBox system is performed seamlessly to the host's application, which stays online throughout the entire process.
  • The procedures is divided into several phases, as described below.

Environment preparation

Preparing the environment for the online data mobility process.

  1. Validate that the source and target systems are properly linked: 
    1. A link was created and it is in UP state.
    2. The link supports Active-Active replication. (Witness configured) 
  2. Zone the host to the target system. 
    • For cluster mobility - zone all the hosts in the cluster to the target system.
    • It is recommended not to pre-register the host (or the entire host's cluster) on the target system as the mobility operation will take care for proper registration. 
  3. Login to the desired host with administrative permission.
  4. Install Host PowerTools v5 and above on the desired host. 
  5. Optional step:
    • Prior to initiating mobility, it's recommended to validate that the mobility test flow completes successfully.
      • For cluster mobility - it is recommended to test all the hosts in the cluster. 
    • Run the 'infinihost mobility test' command:
Infinihost mobility test --source-system=IBOX100 --target-system=IBOX200 --target-pool=TARGET-POOL

Once the environment is prepared, continue to the next phase.

Initiating Mobility

  1. Login to the desired host with administrative permission.
    • On cluster mappings mobility - Login to one of the hosts in the cluster.
  2. Prior to initiating mobility, run the mobility initiate readiness check for the desired volume/s.
      • Run the "infinihost mobility initiate" along with the desired arguments. (without "--yes")
      • This command indicates if the environment is properly configured and the specified volumes are qualified for mobility.
      • On cluster mappings mobility - Login to all the hosts in the cluster and run the mobility initiate readiness check for the desired volume/s on each host.
    • The following example will run the mobility initiate readiness check on all the volumes that are mapped to the host from InfiniBox "IBOX100".

      infinihost mobility initiate --source-system=IBOX100 --target-system=IBOX200 --target-pool=TARGET-POOL
  3. Upon success of step 2, initiate the mobility process on the desired volume/s.
    • By adding "–yes" to the command used on step 2.
    • The following example initiates mobility from system "IBOX100" to system "IBOX200" for all the volume that are mapped to the host from system "IBOX100":

      Infinihost mobility initiate --source-system=IBOX100  --target-system=IBOX200 --target-pool=TARGET-POOL --yes
  4. When the operation is successfully completed, a rescan is performed in order to discover the new LUN/s paths to the target system. 
    • On cluster mappings mobility - Login to each of the hosts in the cluster and perform a rescan in order to discover the new paths to the target system. 
      • A rescan can be performed using the 'infinihost rescan' command.  

Mobility successfully initiated 

After the mobility process was successfully initiated, the source volumes/s data is starting to replicate asynchronously to the target system.

  • Initially the LUN/s paths to the target volume/s are on "Standby" state and cannot serve reads/writes until the mobility replica is synchronized. 

Monitoring the Mobility Progress 

Use the 'Iinfinihost mobility list' command to view the mobility replica/s progress.  

  • On cluster mappings mobility - Run the command on all the hosts in the cluster to validate that each host properly identifies the volumes that are undergoing mobility. 
  • Once the mobility replica state of a specific volume becomes "Synchronized", all it's LUN paths will change the state to Active.
    • New writes would be distributed and acknowledged by both source and target systems.
  • When the mobility replica reaches the "Synchronized" state, the volume can cut-over to the target system.

    Quickly Cut-over synchronized replicas

    It is recommended to minimize the time that mobility replicas are in synchronized state due to the write performance penalty and to reduce link traffic.

Cut-over

Once a mobility replica state becomes "Synchronized" for a specific volume, the cut-over operation can be performed to complete the mobility process of that volume. 

Before performing Cut-over, ensure that the application leverages the OS native multipath software in order to allow a non-disruptive movement to the target system.

  1. Login to the desired host with administrative permission.
    • On clustermappings mobility - Login to one of the hosts in the cluster.

    Cluster mappings mobility

    Before performing Cut-over, ensure that all the hosts in the cluster can access the target volume(s).

  2. Run the cut-over operation on the desired volumes.
    • The following example will try to cut-over all the host's mapped volumes that are undergoing mobility.

Infinihost mobility cut-over
    • On cluster mappings mobility - Login to each of the hosts in the cluster and perform a rescan in order to remove the dead paths to the source system. 
      • A rescan can be performed using the 'infinihost rescan' command. 

Mobility Completed

Volume that successfully cut-over (completed the mobility process) are presented only from the target system. 

Once all volumes cut-over: zoning to the source system should be removed - The Online Data Mobility process is completed for the specific host / cluster.

Troubleshooting

Initiate: Mapping the target-volume fails 

In case the Initiate operation failed to map a target-volume, the mobility replica was already created for the specified source volume.

It is recommended to:

  • Abort the mobility process.
  • Investigate the root cause.
  • Re-initiate mobility.

Host / cluster validation fails

In case any discrepancy is found during the initiate operation between the structure of the source host / cluster and the target host / cluster, the mobility operation aborts.

  • The target host / cluster is considered as not properly registered.
  • It is recommended not to pre-register the host (or the entire host's cluster) on the target system, as the mobility initiate operation will take care for proper registration. 

Try one of the following workarounds:

  • Delete the host / cluster objects on the target system. (In case no other volumes are mapped)
  • Manually edit the host / cluster on the target system to match the source host / cluster.
    • Note to match the object names and the ports each host contains.

Link Down

In case the link between the system is down after the mobility process was initiated, it is not possible to perform any of the mobility operations until the link connectivity is restored.


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