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Replicating an object store

Before you begin

Before you can replicate an object store, you must first make sure:

    Pools with names matching the pools used by the source volume exist on the target system. The destination system has enough free capacity to accommodate the replicated volume (and expected growth). You have created replication floating IPs on both the source and target systems. If you are planning on replicating to an existing application and volume on the target system, the volume must be uninitialized. In other words, the target volume must not have a filesystem, shares, or any mapped initiator hosts. For simplicity, StorONE recommends allowing the replication setup to create a matching application and volume name on the target system. This requires that the application and volume do not exist on the target system. Although it is not required for replication to work, if you want to be able to access the replicated volume at the same IP address regardless of which system is currently hosting the primary, you should have created and paired floating IPs for the volume. You can create and pair floating IPs at any time, even after replication has been configured.

    Starting replication

    You can start replication using the web UI or the command line interface (CLI):

    {{< tabpane text=true >}} {{% tab header="Web UI" %}} In the admin web interface, go to Replication admin. Click the Start button, and fill in the fields:

    Application: Select the application containing the volume you want to replicate.

    Volume: Select the volume that you want to replicate.

    Target System: Select the target system that you want to replicate to.

    Source Floating Ip: Select the replication floating IP entity that you want to use for replication. Most deployments use just one replication floating IP entity per system. In a highly available (HA) deployment, the replication floating IP entity defines two IP addresses: one per controller node. However, this uses a single named configuration entity, so there is only one entry to select in the drop-down menu.

    Target Floating Ip: Select the target replication floating IP entity. As with the source floating IP, in most systems, there is only one target floating IP configuration entity to select that encompasses both floating IPs in an HA system.

    Synchronous, Semisynchronous, or Asynchronous: Select the replication mode you want to use. For more information on these modes, see Replication.

    Parameters

    In the Parameters section, StorONE recommends leaving the fields empty to allow the replication setup to create a matching application and volume on the target system. If you need to pre-create the application and volume (for example, to modify some of the volume settings between the source and target systems), you can do so, but StorONE recommends against it.

    Target Application: If you pre-created an application and volume on the target system, select the application.

    Target Volume: If you selected an existing application, the Target Volume field appears, and you can select an existing volume from that application. The volume must be uninitialized, meaning that it cannot have a filesystem, object store, or have been mapped to an initiator host.

    After completing all fields, click Submit to start replication. You can view the progress by clicking the List button on the Replication page.

    {{% /tab %}} {{% tab header="CLI" %}} To start replication using the CLI, use the following command:

    replication start --application=<name> --volume=<name> --targetSystem=<name>
[(--targetApplication=<name> --targetVolume=<name>)]
  --sourceFloatingIp=<name> --targetFloatingIp=<name>
  --synchronous | --semisynchronous | --asynchronous
 [--force]

    --application=<name>

    Specify the application containing the volume you want to replicate. You can use the TAB key auto-complete to list available applications.

    --volume=<name>

    Specify volume you want to replicate. You can use the TAB key auto-complete to see the available volumes.

    --targetSystem=<name>

    Specify the target system that you want to replicate to. You can use the TAB key auto-complete to see the available systems.

    --targetApplication=<name> --targetVolume=<name>

    These parameters are optional, but mutually inclusive. If you specify them, you must specify both. StorONE recommends omitting these parameters to allow the replication setup to create a matching application and volume on the target system. If you need to pre-create the application and volume (for example, to modify some of the volume settings between the source and target systems), you can do so, but StorONE recommends against it.

    --sourceFloatingIp=<name>

    Specify the replication floating IP entity that you want to use for replication. Most deployments use just one replication floating IP entity per system. In a highly available (HA) deployment, the replication floating IP entity defines two IP addresses: one per controller node. However, this uses a single named configuration entity, so there is only one floating IP to specify. You can use the TAB key auto-complete to see the available replication floating IPs.

    --targetFloatingIp=<name>

    Specify the target replication floating IP entity. As with the source floating IP, in most systems, there is only one target floating IP configuration entity to select that encompasses both replication floating IPs in an HA system. You can use the TAB key auto-complete to see the available target replication floating IPs.

    --synchronous | --semisynchronous | --asynchronous

    Specify the replication mode you want to use. For more information on these modes, see Replication.

    --force

    Skip the confirmation prompt.

    Examples

      To asynchronously replicate the homedir volume in the users application to a target system named acme-dr, and have the system create a matching application and volume on the target system:

      replication start --application users --volume homedir --targetSystem acme-dr --sourceFloatingIp repl-float --targetFloatingIp repl-float --asynchronous

      To synchronously replicate the ds01 volume in the vm application to an unitialized volume named ds01-repl in the vm-repl application within the us-repl target system:

      replication start --application vm --volume ds01 --targetSystem us-repl --targetApplication vm-repl --targetVolume ds01-repl --sourceFloatingIp replication-ip --targetFloatingIp replication-ip --synchronous

      {{% /tab %}} {{< /tabpane >}}

      Configure object store and floating IPs

      To be able to access a replicated object store on a target system, you must create an object store with a paired floating IP.

      If you have not already done so, create floating IPs on the source and target systems, and pair them together. Assign a real IP address to the floating IP on the system hosting the primary volume, and specify the other as a standby ("dummy") IP. When you initiate a replication transition, you specify the standby floating IP to activate.

      Then, make sure that the paired floating IPs are assigned to the object stores in the source and target systems:

      {{< tabpane text=true >}} {{% tab header="Web UI" %}} To see which floating IP is assigned to the object store, in the admin web interface, go to Applications admin > Objects admin > Stores admin.

      If the paired floating IP you want to use is not listed on the object store:

        Click the Edit button. In the Volume Selection section, select the application and volume. In the Editable Values section, select the paired floating IP that you want to use for the object store from the Floating Ip drop-down menu. Click Submit to save your changes. Repeat on the other system.

        {{% /tab %}} {{% tab header="CLI" %}} Run the following command to see the floating IPs assigned to the object store:

        applications objects stores list

        If the paired floating IP you want to use is not listed, edit the object store to set it:

        applications object stores edit --application=<application_name> --volume=<volume_name>  --floatingIp=<floating_ip>

        --application=<application_name> --volume=<volume_name>

        Specify the application and volume names. You can use the TAB key auto-complete to list the applications and volumes.

        --floatingIps=<floating_ip...>

        Specify the floating IPs to associate with the object store. You can use the TAB key auto-complete to list the available floating IPs.

        {{% /tab %}} {{< /tabpane >}}

        Monitoring replication status

        You can view the replication status using the web UI or the CLI:

        {{< tabpane text=true >}} {{% tab header="Web UI" %}} In the admin web interface, go to Replication admin.

        The Sync entry shows the replication status. In the Parameters sections, you can specify an application and volume to see the status of a specific replicated volume. You can also use the Filter Secondary and Filter Primary radio buttons to display only secondary or primary volumes, respectively.

        Click Submit to view the results after specifying any custom parameters.

        {{% /tab %}} {{% tab header="CLI" %}} Run the following command to see the replication status in the CLI:

        replication list

        If you want to see only specific volumes, you can use the following parameters:

        replication list [--application=<name> --volume=<name>] [--filterSecondary|--filterPrimary]

        {{% /tab %}} {{< /tabpane >}}

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