Creating and managing replication in PowerStore Manager is easy and intuitive. All replication operations, including configuring of replication network ports, replication connections, and replication sessions, can be performed in the PowerStore Manager UI. With the help of wizards, replication can be configured by IT generalists or by advanced users. Replication can also be configured using the PowerStore Manager CLI or REST API. For more information about configuring and managing replication using the PowerStore Manager CLI, see the Dell PowerStore Manager Command Line Interface Guide. For more information about the REST API, use SwaggerUI (https://<PowerStore_Cluster_IP>/swaggerui) or see the Dell PowerStore REST API Programmer’s Guide.

The following sections outline the remaining steps that are required to configure remote replication in PowerStore Manager. Each of the following operations is completed from a particular page in PowerStore Manager. Each page is discussed in detail in the following sections. For more information about using PowerStore Manager to configure and manage replication, see PowerStore Manager Online Help.

Storage network IPs and replication ports

When planning replication between two PowerStore arrays, consider the following:

• Only one interface or system bond can be tagged for replication. If the system bond interfaces are connected to different switches, replication can continue even if one switch is down.
• When file service is configured, configure a link aggregation interface for file services when using system bond for replication traffic.
• When host traffic is configured on an interface tagged for replication, the available bandwidth is shared. This configuration can have an impact on performance.
• If host traffic and replication traffic are using the same network but different ports, configure host multipathing without using ports tagged for replication.
• In a configuration with multiple IP networks, the IP address ranges must not overlap with existing IP address ranges configured on the system.
• Only storage networks that are configured with an iSCSI purpose can be tagged for replication.
• Depending on workload and data change rate on replicated volumes, a higher port speed might be required to steadily meet the RPO target for asynchronous replication and for continuous replication of Metro Volumes.

This section shows the configuration for shared network ports as it has been supported since PowerStoreOS 1.x. A single storage network is used for host I/O or import, and replication-related data using the storage network. PowerStoreOS 2.x and later allows different storage networks for host access and replication data network. Starting with PowerStoreOS 3.0, it is also possible to use different ports than system bond for file I/O and to create additional link aggregation for file I/O.

Each port for a storage network configuration on a PowerStore requires its own IP address. When it is planned to extend an existing storage network, check the available storage IP addresses before creating interfaces. To verify the settings for storage network IPs, select Settings > Networking > Network IPs. Ensure that at least two storage network IPs for each appliance in the cluster configuration are unallocated for mapping new storage network ports which are distributed across the nodes. To tag new replication ports in PowerStore Manager, select Hardware > Appliance-Name, and select the Ports tab. All Ethernet ports and system-bond are eligible to be tagged as replication ports and are available in the ports list.

Figure 5 shows the PowerStore Manager Ports page. The figure also shows the default Link Aggregation ports (system-bond/bond0) that are set up on the system and are already tagged for replication using Default Storage Network, which was created beforehand. From this page, you can map ports to the storage network and change the tagging of replication data interfaces.

Figure 5.   Ports overview page

To change the replication data port to a port other than the system bond or vFE1 Port on port group TGT1, map a new set of ports to the storage network. It is only required to run these steps for a single node. PowerStore Manager configures the peer node in parallel.

The example in Figure 6 shows how to map a storage network:

1. Select the port.

2. Click MAP STORAGE NETWORK.

If only a single port is selected, PowerStore Manager automatically configures the corresponding port on the peer node.

3. Select the storage network to be mapped.
4. Confirm the selected mapping with MAP STORAGE.
5. To finish the configuration, confirm the following dialog.

Figure 6.   Map Storage Network

After ports are mapped to the storage network, select MORE ACTIONS > Tag for Replication, as shown in Figure 7. In the resulting window, click TAG PORT to finish the configuration. When it is set, the replication tag cannot be removed completely, but it is possible to reconfigure the replication tag for a different port or to a different storage network. Similar to mapping, it is always a pair of ports that are tagged for replication—one port on Node A and a corresponding port on Node B.

Figure 7.   Tag port for replication

Individual networks for host and replication traffic

Starting with PowerStoreOS 2.0, multiple storage networks are supported. This feature allows users to separate host data from replication data either using same or different ports.

The following examples are using Default Storage Network and Replication Network (Figure 8) as already configured networks in PowerStore Manager (configured by selecting Settings > Networking > Network IPs > Storage).

Figure 8.   Multiple storage networks

Example 1: Two storage networks over a single port

When physical links for storage network are not fully used by host data, it might be useful to set up a shared port for host data and replication data. To separate the traffic, it is required to set up VLANs on the switch ports. This example is using VLAN 320 for host access and VLAN 308 for replication traffic. The configured VLANs in PowerStore Manager must match the switch port configuration (VLAN tagging). As in previous sections, the port configuration in PowerStore Manager is available in the Hardware > Appliance-Name > Ports view. Figure 9 shows the current configuration where system bond is tagged for host I/O and replication using the mapped storage network Default Storage Network.

Figure 9.   Single network configuration

For replication tagging, configuring the additional storage network is required. Replication Network as the second Storage Network for the port pair was created in network settings in advance. Because the port configuration is the same on partner nodes, it is only required to select one single port for configuration and use the MAP STORAGE NETWORK button. In the selection window that is displayed, choose the Replication Network and continue with MAP NETWORK (Figure 10).

Figure 10.    Map Storage Network

When the Map Storage Network dialog is confirmed, the port overview column Mapped for Storage changes to 2, which indicates that two storage networks are mapped and using this port. Hovering over the number shows the IP address information for the ports (Figure 11).

Figure 11.    Detailed port information

The mapped network can be tagged as a replication network as in a single network configuration. Now you can choose the network used to tag the selected port, as shown in Figure 12.

Figure 12.    Tag for Replication – Network selection

After the dialog to perform configuration on both nodes is confirmed, the tagged network for replication changes to the new Replication Network (Figure 13).

Figure 13.    Single port configuration with dedicated network tagged for replication

Example 2: Separated host and replication networks

Note: This example uses the system bond as a replication port, which might not be the optimal configuration for all use cases.

In some use cases, it might be useful to separate the replication data network from production host traffic by using different physical ports and networks. The configuration is similar to Example 1. The difference is to map the Replication Network to another port than the Default Storage Network, which is used for host traffic. The example in Figure 14 shows a selected port with a dialog box to select the storage network for mapping.

Figure 14.    Map replication network to a new network port

After the configuration is finished, it is possible to tag the new storage network port for replication. Because only one storage network is configured in our example, there is no additional dialog to select the network. The port is tagged with Replication Network after the configuration is confirmed. Figure 15 shows the configuration for that example.

Figure 15.    Port configuration with dedicated host and replication storage network

Remote systems

The next step in configuring remote replication is to create a remote systems pair with another system. This step configures a private replication connection using the management ports. To set up a replication connection, select Protection > Remote Systems to start creating remote systems (see Figure 16).

Figure 16.    Remote systems replication setup

To define a new remote system, click ADD as shown in Figure 16. The Add Remote System window that is displayed (Figure 17) requires the following information:

• Management Cluster IP Address
• Username and Password of the remote system
• Network Latency setting

Figure 17.    Add Remote System

Replication traffic can be tuned for higher efficiency depending on the expected network latency. When network latency between the remote systems is unknown, use the ping utility to determine the latency. For PowerStoreOS releases 1.x and 2.x, use Low when the expected latency is less than 5 milliseconds, otherwise use High. PowerStoreOS 3.0 and later allows a more granular setting of network latency, as shown in Figure 17.

The provided credentials for a configured user are not stored on the system and are only used for the relationship setup. After the relationship is set up, PowerStore uses SSL certificate-based authentication. When the required fields are entered, click ADD. Because the management connection for the remote systems pair uses SSL encryption, it is required to confirm the remote SSL certificate. After the configuration task is finished, the new remote system is listed on both sides. If using bi-directional replication, the same remote systems pair can be used for replication sessions from the opposite systems.

After a remote system is set up, select MORE ACTIONS > Verify and Update. This action verifies that the selected replication connection still exists with the remote system, and it updates the connection details if any changes were made. Figure 18 shows the Remote Systems Overview. The Capability column indicates the supported types of replications for the remote system pair. The Management/File State and Data Connection columns indicate the link status.

Figure 18.    Remote Systems Overview

Replication data network

For PowerStoreOS releases 1.x and 2.x, the iSCSI protocol is used for replication data traffic. PowerStoreOS 3.0 and later leverages a TCP-based protocol for replication data traffic. The TCP-based replication protocol improves replication performance between systems with network impairment, such as high latency or packet loss. Replication between earlier releases and PowerStoreOS 3.0 is supported and relies on the iSCSI protocol. Each latency category uses a different network port number. For replication across network borders, adjusting network ACL or network firewall rules might be required to allow replication traffic. Table 3 shows an overview of different network latency settings and the network port that is used on PowerStore.

Table 3.      Remote systems network latency overview

File mobility network

File replication requires an additional file mobility network configuration for control traffic between the clusters. The file mobility network resides in the same subnet as the PowerStore cluster management network and requires three additional IP addresses in that range. While PowerStoreOS 3.0 does not support any changes when a file replication is configured, PowerStoreOS 3.2 supports deleting and changing the file mobility network in a paused state without needing to delete the existing replication sessions. Even though a deletion of the file mobility network is supported, it is required when replication sessions are activated again.

The configuration for file mobility network (Figure 19) can be found on the File Mobility tab at Settings > Networking > Network IP. When the initial network configuration is finished, map the file mobility network to the PowerStore management ports of the appliance. For the Reconfigure or Delete tasks (PowerStore 3.2 and later), a dialog is displayed to confirm that no active file migrations or replication sessions are in place.

Figure 19.  
Create file mobility network