In order to understand how SyncIQ implements each policy, it is essential to understand the processes associated with data replication as illustrated in the following figure.
Each PowerScale node has a Scheduler process running. It is responsible for the creation and launch of SyncIQ data replication jobs and creating the initial job directory. Based on the current SyncIQ configuration, the Scheduler starts a new job and updates jobs based on any configuration changes.
The Scheduler launches the Coordinator process. The Coordinators create and oversee the worker processes as a data replication job runs. The Coordinator is responsible for snapshot management, report generation, bandwidth throttling, managing target monitoring, and work distribution.
Snapshot management involves capturing the file system snapshots for SyncIQ. The snapshots are locked while in use and deleted after completion. Report management acquires job data from each process and combines this to a single report. Bandwidth throttling provides the Coordinator with bandwidth information to align jobs with available bandwidth. Target monitoring management is monitoring the target cluster’s worker process. And finally, work distribution maximizes job performance by ensuring all worker process have even utilization.
Primary workers and secondary workers run on the source and target clusters, respectively. They are responsible for the actual data replication piece during a SyncIQ job.
The target monitor provides critical information about the target cluster and does not participate in the data transfer. It reports back with IP addresses for target nodes including any changes on the target cluster. Additionally, the target monitor takes target snapshots as they are required.