Administrator Guide

Working in the Replications topic
Topics:
• About replicating virtual volumes in the Replications topic
•
Viewing replications
• Querying a peer connection
• Creating a peer connection
• Modifying a peer connection
• Deleting a peer connection
• Creating a replication set from the Replications topic
• Modifying a replication set
• Deleting a replication set
• Initiating or scheduling a replication from the Replications topic
• Stopping a replication
• Suspending a replication
• Resuming a replication
• Manage replication schedules from the Replications topic
About replicating virtual volumes in the Replications
topic
Replication for virtual storage provides a remote copy of a volume, volume group, or snapshot—thereafter known as volume—
on a remote system by periodically updating the remote copy to contain a point-in-time consistent image of a source volume.
After an initial image has been replicated, subsequent replications only send changed data to the remote system. All replications,
including the initial one, only replicate data that has been written as opposed to using all pages of data from the source. This
feature can be used for disaster recovery, to preserve data, and to back data up to off-site locations. It can also be used to
distribute data.
Replication prerequisites
To replicate a volume, you must first create a peer connection and replication set. A peer connection establishes bi-directional
communication between a local and remote system, both of which must have FC or iSCSI ports and a virtual pool. The system
establishes a peer connection by connecting a host port on the local system with a user-specified host port on the remote
system, then exchanging information and setting up a long term communication path in-band. Because the communication path
establishes a peer connection between the two systems, replications can occur in either direction.
To verify that a host port address is available before creating a peer connection, use the query peer-connection CLI
command. This command provides information about the remote system, such as inter-connectivity between the two systems,
licensing, and pool configuration. For more information on this command, see the Dell EMC PowerVault ME4 Series Storage
System CLI Guide. For more information on peer connections, see Creating a peer connection, Deleting a peer connection, and
Modifying a peer connection.
After you create a peer connection, you can create a replication set. A replication set specifies a volume, snapshot, or multiple
volumes in a volume group (hereafter known as volume) on one system of the peer connection, known as the primary system
in the context of replication, to replicate across the peer connection. When you create a replication set, a corresponding
volume is automatically created on the other system of the peer connection, known as the secondary system, along with the
infrastructure needed for replication. The infrastructure consists of internal snapshots used for replication operations:
● A replication set for a volume consumes two internal snapshots each for the primary volume and the secondary volume if the
queue policy is set to Discard, or three each if the queue policy is set to Queue Latest.
8
Working in the Replications topic 117