Creating and Managing a Continuous Replication Relationship in Qumulo Core

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

How Continuous Replication Works

Important
Qumulo Core supports replication between different versions only if either the source or target cluster is running Qumulo Core 2.12.0 (or higher). For more information, see Replication Version Requirements

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.

Note

We don't recommend granting the following privileges to specific users because they grant administrative access to your cluster.
The following privileges grant user access to Qumulo Core functionality beyond replication relationship management:
- PRIVILEGE_REPLICATION_SOURCE_WRITE: Grants the permission to access any data on a cluster, regardless of file or directory permissions
- PRIVILEGE_REPLICATION_TARGET_WRITE: Grants the permission to authorize replication relationships to any target directory on a cluster

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

Important
A replication job doesn’t begin until you authorize the relationship on the target cluster.

Log in to the Qumulo Core Web UI on the source cluster.
Click Cluster > Replication.
On the right side of the Replication Relationships page, click Create Relationship.
On the Create Replication Relationship page:
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.
  
  Tip
  We recommend using a floating IP address.
4. For Port Number, click Default (3712) or enter a custom port.
  Note
  - Every node on the target cluster uses port 3712 to listen for incoming replication connections.
  - If a source cluster is unable to reach a target cluster on port 3712, you must configure your firewall, by mapping an external IP address and port number to the target cluster's IP address and port number.
Click Add Blackout Window and then select the days of the week and time when replication suspends.
(Optional) To add another blackout window, click Add Blackout Window.

Note
You can add up to ten blackout windows. For more information, see Replication: Blackout Windows on Qumulo Care.
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.
Under Enable Replication, click Enabled.
Click Save Relationship.

To Authorize a Replication Relationship

Note
If your cluster is currently in a blackout window or if continuous replication for the replication relationship is disabled, replication doesn’t begin. For more information, see Replication: Blackout Windows on Qumulo Care.

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

A notification banner informing you of a new relationship authorization request appears.
On the banner, click See details.
On the Replication Relationships page, click Accept.

To View the Status of a Replication Relationship

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
	The replication is running or is ready to run.
	The replication is awaiting authorization from the target cluster's administrator.
	The replication relationship is disconnected and the target directory is writable.
	The replication relationship is in a blackout window.
	Continuous replication is disabled.
	The target directory is reverting to the last recovery point before becoming writable.
	The replication job is incomplete and will retry soon.

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

Note
The replication process percentage considers the number of files to be replicated and the amount of data to be transferred.

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

To Modify a Replication Relationship

Note
It isn’t possible to edit the source and target directory paths. To make these changes, you must create a new replication relationship.

Log in to the Qumulo Core Web UI.
Click Cluster > Replication.
On the Replication Relationships page, next to the relationship to modify, click > Edit Relationship…
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

Log in to the Qumulo Core Web UI.
Click Cluster > Replication.
On the Replication Relationships page, next to the relationship to delete, click > Delete Relationship…
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.