This section explains how to create, authorize, modify, and delete a replication relationship by using the Qumulo Core Web UI.

How Continuous Replication Works

Continuous replication takes a snapshot of the data in a directory on the source cluster and transfers it to a directory on the target cluster. While continuous replication runs, Qumulo Core scans modified files for any changed regions and transfer only these changes to the target cluster.

Continuous replication uses snapshots to generate a consistent point-in-time copy of the source directory on the target cluster. To ensure that a directory contains only the most recent snapshot, Qumulo Core deletes previous snapshots automatically. Administrators can view the snapshots used for replication and any other policy-based snapshots.

Prerequisites

The following privileges are required for continuous replication.

  • Creating a replication relationship
    • SOURCE_WRITE: For the user on the source cluster to initiate the creation of the relationship
    • TARGET_WRITE: For the user on the target cluster to authorize the relationship
  • Viewing the replication relationship status
    • PRIVILEGE_REPLICATION_SOURCE_READ
    • PRIVILEGE_REPLICATION_TARGET_READ

To Create a Replication Relationship

  1. Log in to the Qumulo Core Web UI on the source cluster.

  2. Click Cluster > Replication.

  3. On the right side of the Replication Relationships page, click Create Relationship.

  4. On the Create Replication Relationship page, do the following:

    1. For Source Directory Path, enter the existing directory from which to replicate data.

    2. For Target Directory Path, enter the existing directory to which to replicate data.

    3. For Target Address, enter one of the IP addresses from a node on the target cluster.

    4. For Port Number, click Default (3712) or enter a custom port.

  5. Click Add Blackout Window and then select the days of the week and time when replication suspends.

  6. (Optional) To add another blackout window, click Add Blackout Window.

  7. To replicate files by using locally-owned NFS IDs, under Map Local User/Group IDs to Associated NFS IDs, click Enabled.

    For more information, see Replication: NFS ID Mapping on Qumulo Care.

  8. Under Enable Replication, click Enabled.

  9. Click Save Relationship.

To Authorize a Replication Relationship

  1. Log in to the Qumulo Core Web UI on the target cluster.

    A notification banner informing you of a new relationship authorization request appears.

  2. On the banner, click See details.

  3. On the Replication Relationships page, click Accept.

To View the Status of a Replication Relationship

  1. Log in to the Qumulo Core Web UI on the source cluster.

  2. Click Cluster > Replication.

    The Replication Relationships page shows a list of source and target clusters. The following table explains the icons that appear between the Source and Target columns.

    Icon Description
    Replication is Running
    		 The replication is running or is ready to run.
    Replication is Awaiting Authorization
    		 The replication is awaiting authorization from the target cluster's administrator.
    Replication Relationship is Disconnected
    		 The replication relationship is disconnected and the target directory is writable.
    Replication Relationship is in a Blackout Window
    		 The replication relationship is in a blackout window.
    Continuous Replication Disabled
    		 Continuous replication is disabled.
    Target Directory is Reverting to the Last Recovery Point
    		 The target directory is reverting to the last recovery point before becoming writable.
    Replication Job is Incomplete
    		 The replication job is incomplete and will retry soon.

    A progress bar in the Status column indicates the replication process.

  3. To review the throughput, run time, and data statistics for the replication job in progress, click Details.

To Modify a Replication Relationship

  1. Log in to the Qumulo Core Web UI.

  2. Click Cluster > Replication.

  3. On the Replication Relationships page, next to the relationship to modify, click Vertical Ellipsis > Edit Relationship…

  4. Make changes to your replication relationship (for more information, see To Create a Replication Relationship) and then click Save Relationship.

To Delete a Replication Relationship

  1. Log in to the Qumulo Core Web UI.

  2. Click Cluster > Replication.

  3. On the Replication Relationships page, next to the relationship to delete, click Vertical Ellipsis > Delete Relationship…

  4. In the Delete relationship dialog box, review the source and target clusters and then click Yes, Delete.

Known Continuous Replication Limitations in Qumulo Core

  • Continuous Replication: Depending on applications in use while a replication job runs, continuous replication increases the load on the cluster and can cause latency delays.
  • Local Users and Groups: Continuous replication doesn't support replicating local user or group information and fails when it encounters a file associated with local users or groups.
  • Target Directory Permissions When you create a replication relationship, Qumulo Core updates these permissions from read-write to read-only. When you delete the relationship, the permissions revert to read-write automatically.
  • Root Directory: Including this directory makes the entire target cluster read-only and might prohibit administrative functions such as upgrades. For more information, see Replication Version Requirements and Upgrade Recommendations
  • Upgrades During Replication: Before you perform any Qumulo Core upgrades, you must wait until the replication job is complete. Upgrading Qumulo Core while a replication job is in progress causes the job to fail. When both clusters return to a state where replication is possible (the versions are the same), continuous replication can continue.