5.6. Site Sync

Ngenea Hub provides the facility for syncing data from one site to another.

Site Sync applies changes in one direction. See also Bidirectional Site Sync for applying changes in both directions.

Synchronisation is achieved by utilising a scheduled workflow which periodically discovers file and directory changes within an Independent Fileset on a source site and applying those changes to a target site. Changes are applied by sending newly created or recently modified files and directories, including deleting or moving files or directories in place on the target site as necessary to match the source site.

The following walkthrough details how to set up a sync between two sites ('Site Sync') using the Ngenea Hub UI.

The REST API can also be utilised to achieve the same setup.

5.6.1. Schedule

A schedule defines when and how often a sync occurs.

In the Ngenea Hub UI, navigate to the Administration page, and select the Schedules tab.

To create a new schedule, click the Add button.

Configure the schedule by entering appropriate details into the Add new schedule dialog:

1. Enter a descriptive Name for the schedule, E.G. "sync-to-site2"

2. Select the source site from the dropdown menu

3. Set the Discovery to snapdiff. Snapdiff discovery uses snapshots to track changes over time within an Independent Fileset.

4. Set the Path to the top level directory (path) of the Independent Fileset to be synchronised

5. Set the time criteria

6. Click the Add button to add the new schedule

Time criteria

A schedule utilises cron syntax. By default, all the fields are populated with * - this means the schedule will run every minute. This is likely too frequent as the calculation of file changes could take longer than the time between the schedule running every minute. Sizing for an ideal setup will balance the need to sync files quickly versus how long the sync snapdiff stage takes to run. This can be most effectively achieved through observation.

Examples:

• To enact the schedule every 5 minutes, specify the Minute field as follows: */5.

• To enact the schedule once an hour, set the Minute field to a number of minutes past the hour. Setting Minute to 5 will run the sync once an hour at 5 minutes past the hour.

• To enact the schedule at set times throughout the hour, change the Minute field separating entries by commas (E.G.) 7,23,46

5.6.2. Workflow

Schedules enact a workflow. A workflow performs one or more series of tasks to files and/or directories.

In the Ngenea Hub Hub UI, navigate to the Administration page, and select the Schedules tab.

Select the prior created schedule in the Schedules tab, which then displays the Schedule Details page.

Subscribing a workflow

To associate a workflow with a schedule undertake the following actions:

1. Click Subscribe and in the create dialogue set Site to the source site from which to synchronise.

Ngenea Hub provides a built-in workflow for synchronising changes from an Independent Fileset on a source site to a target site.

2. Select Sync Fileset to Site from the Workflow dropdown menu.

Configure the workflow subscription settings by entering appropriate details into the Subscribe workflow to schedule dialog:

1. Select the target site in the Destination site

2. Select an appropriate Sync Policy

3. Click Subscribe to associate the workflow to the schedule

Sync Policy

The Sync Policy setting controls how conflicts are resolved. A conflict may occur if (E.G.) different versions of the same file exist on both source and target sites. By default, the newest version of the file will be retained.

Outcome

Now associated (subscribed), files and/or directories will synchronise at the next scheduled execution time. When executing the scheduled workflow, two jobs appear within the schedule details page. One for the snapdiff discovery, and one for the subscribed sync workflow.

The first enactment of the sync will synchronise all files and directories in the Independent Fileset from the source site. Further enactments will synchronise files and/or directories created, modified, deleted or moved since the last enactment and the time of the most recent enactment.

5.6.3. Additional Options

Associating more than one workflow to the same schedule can be utilised to synchronise from the same source site to another target site. Additional workflows cause creation of an additional job, and run simultaneously with other syncs enacted from the same schedule.

5.6.4. Troubleshooting

If you encounter issues with sync, refer to the sync troubleshooting guide page for guidance.