Dell PowerFlex 4.6.x Technical Overview

Storage data replicator

Storage data replicators process all I/Os of replication volumes.

The source storage data replicators processes all application I/Os of replicated volumes. At the source, the SDC sends application I/Os to the storage data replicator. The I/Os are sent to the target storage data replicators and stored in their journals. The journals of the target storage data replicators apply the I/Os to the target volumes. A minimum of two storage data replicators are deployed at both the source and target systems to maintain high availability. If one storage data replicator fails, the MDM directs the SDC to send the I/Os to an available storage data replicator.

The source storage data replicator processes all application I/Os of replicated volumes. The source storage data replicator saves changes to the journal, and later sends them to the target storage data replicators. At the target, the storage data replicators receive the changes, and when a consistent image is available, apply the changes to the target volumes.

A minimum of two SDRs are deployed at the source and target protection domain to ensure high availability.

The ratio of SDRs in a source protection domain to the storage data replicators in its target protection domain is limited. The maximum ratio of peer storage data replicators is 1:6, and the maximum ratio of storage data replicators in maintenance is 1:18. The Add_SDR and Remove_SDR commands fail if the operation results in an unsupported ratio. If the storage data replicators ratio exceeds the allowed value as a result of a failure or planned maintenance, the Add_RCG command fails. Existing replication consistency groups and replication operations are not impacted.