Mirroring

Synopsis of mirrors and mirroring process.

Creating a mirror volume is similar to creating a normal read/write volume. However, when you create a mirror volume, you must specify a source volume from which the mirror retrieves content. This retrieval is called the mirroring operation. Like a normal volume, a mirror volume has a configurable replication factor. Only one copy of the data is transmitted from the source volume to the mirror volume. HPE Ezmeral Data Fabric volumes can only be mirrored and NOT replicated. However, the source and mirror volumes handle their own internal HPE Ezmeral Data Fabric filesystem replication (which is based on the replication factor) independently. file system internally replicates source and mirror volumes independently of each other.

Volume mirroring from a lower HPE Ezmeral Data Fabric version to higher HPE Ezmeral Data Fabric version is supported. Volume mirroring from a higher Data Fabric version to a lower Data Fabric version is not supported.

Mirroring Process

The HPE Ezmeral Data Fabric system creates a temporary snapshot of the source volume at the start of a mirroring operation. The mirroring process reads content from the snapshot into the mirror volume. The source volume remains available for read and write operations during the mirroring process.

If the mirroring operation is schedule-based, the snapshot expires according to the value of the schedule's Retain For parameter. Snapshots created during manual mirroring persist until they are deleted manually.

The mirroring process transmits only the differences between the source volume and the mirror. The initial mirroring operation copies the entire source volume, but subsequent mirroring operations can be extremely fast.