Configuring IP replication

Configuring IP replication with remote systems or sites requires that you follow a specific set of steps, such as creating a partnership and configuring the replication between the production site and other remote sites.You can configure IP replication over Ethernet ports that use IPv4 or IPv6 connections.

Metro Mirror and Global Mirror partnerships can be established over Ethernet links that use the IPv4 and IPv6 addresses associated with Ethernet ports. These IP partnerships can be connections through Ethernet switches, or direct connections between local and partner systems. Partnerships must be created as either an IPv4 or IPv6 partnership. Data compression is also supported for IPv4 or IPv6 partnerships. To enable data compression, both systems in an IP partnership must be running a software level that supports IP partnership compression. To fully enable compression in an IP partnership, each system must enable compression. When compression is enabled on the local system, data sent to the remote system is compressed. To send compressed data to the local system, the remote system in the IP partnership must also enable compression.

Portsets replace the requirement for creating remote-copy groups for IP partnerships. Dedicated portsets can be created for remote copy traffic. The dedicated portsets provide group of IP addresses for IP Partnerships. Each node can have one IP address that is assigned to a portset for remote-copy traffic. If the local system in the IP partnership contains four nodes, a portset can be created that defines four IP addresses, one per each node. Similarly, the remote system with four nodes, a portset on that system can also have four IP addresses to handle remote-copy traffic exclusively. During updates of the software, any IP addresses that are assigned to remote copy groups with an existing IP partnership are automatically moved to a corresponding portset. For example, if remote-copy group 1 is defined on the system before the update then IP addresses from that remote-copy group are mapped to portset 1 after the update. Similarly, IP address in remote-copy group 2 is mapped to portset 2. Before you can configure a new IP partnership, you need to define a portset and assign IP addresses to nodes.

Using the management GUI

Create a portset

Select Settings > Network > Portsets.
Select Create Portset.
On the Create Portset page, enter a name of the portset, and select Remote Copy for the portset type.
Select the ownership group for the portset. An ownership group defines a subset of users and objects within the system. You can create ownership groups to further restrict access to specific resources that are defined in the ownership group. Only users with Security Administrator roles can configure and manage ownership groups. Restricted users are those users who are defined to a specific ownership group and can only view or manage specific resources that are assigned to that ownership group. Unrestricted users are not defined to an ownership group and can manage any objects on the system based on their role on the system. When you define an ownership group for portsets, you can limit and restrict users to view and manage only specific portsets.
Click Create.

Assign IP addresses to the portset

Select Settings > Network > Ethernet Ports.
Right-click the port and select Manage IP addresses.
On Manage IP Addresses page, select Add IP Address. Enter the following information for the IP address that you are adding to the selected port:

IP address

Enter the IP address to associate with the selected port.

Type

Select the IP protocol version of the IP address.

Subnet Mask or Prefix

Enter the subnet mask for the IPv4 addresses or enter the prefix for IPv6 addresses.

VLAN

Enter the corresponding VLAN tag that this IP address belongs to.

Portset

Select the name or ID of the portset and ensure that portset type matches the traffic type that is assigned to the port.
Click Back to return to the Ethernet Ports page. Verify that the port displays the Configured state. Select another port and add more IP addresses to corresponding portsets.
Right-click the port and select either Modify Remote Copy, Modify iSCSI hosts, or Modify Storage Ports. The traffic type for the port must match the traffic for the portset that you created.

Create the IP partnership

Select Copy Services > Partnerships and select Create Partnership.
Select 2-Site Partnership and click Continue.
On the Create Partnership page, select IP.
Enter the following information to configure the partnership:

Partner System IP Address

Select the IP address of the partner system.

Link Bandwidth

Enter the amount of bandwidth used for replication between systems in the partnership.

Background Copy Rate

Enter the maximum percentage of the link bandwidth that can be used for background copy operations.

Partner System's CHAP Secret (Optional):

Specify the CHAP secret for the partner system if you plan to use Challenge Handshake Authentication Protocol (CHAP) to authenticate connections between the systems in the partnership.

Compression enabled

Select this option if data on the local system is compressed before it is sent to the partner system. To fully enable compression in an IP partnership, each system must support compression.
Note: Compression is not supported on

Portset Link 1

In single link configurations between partnered systems, select the portset that provides IP addresses for remote-copy traffic.

Portset Link 2

In dual link configurations between partnered systems, select the portset that provides IP addresses for remote-copy traffic. Dual links provide redundancy for connections between systems.

Upload Certificate

To secure the connection between the systems in the partnership, upload the certificate. Both CA certificates and self-signed certificates are supported.
Repeat these steps on the remote system in the partnership.

Create a remote-copy relationship

A remote-copy relationship configures replication between source volumes at the production site and auxiliary volumes at the remote site. To create a remote-copy relationship, complete these steps:

In the management GUI, select Copy Services > Remote Copy.
Select the Independent Relationships tab.
Click Create Relationship.
Select the one of following types of relationships and click Next.

Metro Mirror

This remote-copy type creates a synchronous copy of data from a master volume to an auxiliary volume. An auxiliary volume can either be on the same system or on another system. Metro Mirror can be used between volumes that are separated by distances up to 300 km. For disaster recovery purposes, Metro Mirror provides the simplest way to maintain an identical copy on both the primary and secondary volumes. However, like with all synchronous copies over remote distances, performance on host applications can be impacted. This performance impact is related to the distance between primary and secondary volumes and depending on application requirements, its use might be limited based on the distance between sites.

Global Mirror

The Global Mirror remote-copy type provides an asynchronous copy process. When a host writes to the primary volume, confirmation of I/O completion is received before the write operation completes for the copy on the secondary volume.
If a failover operation is initiated, the application must recover and apply any updates that were not committed to the auxiliary volume. If I/O operations on the primary volume are paused for a small length of time, the auxiliary volume can become an exact match of the primary volume. This function is comparable to a continuous backup process in which the last few updates are always missing. When you use Global Mirror for disaster recovery, you must consider how you want to handle these missing updates.

Global Mirror with Change Volumes

Global Mirror with change volumes provides the same basic function of asynchronous copy operations between source and target volumes for disaster recovery. However, a separate volume is created to track changes and copy-on-write technology is used to maintain the consistent image of the primary volume for the background copy process to read.
If you are using Global Mirror with change volume, the copying process is similar to Metro Mirror and standard Global Mirror. Change volumes must be configured for both the primary and auxiliary volumes in each relationship. A copy is taken of the primary volume in the relationship that uses the change volume that is specified when the Global Mirror relationship with change volumes is created. The background copy process reads data from the stable and consistent change volume, copying the data to the auxiliary volume in the relationship. Copy-on-write technology is used to maintain the consistent image of the primary volume for the background copy process to read. The changes that took place while the background copy process was active are also tracked. The change volume for the auxiliary volume can also be used to maintain a consistent image of the auxiliary volume while the background copy process is active. Global Mirror with change volumes help eliminate the missing updates that can occur when you use Global Mirror without change volumes.
Select the location of the auxiliary volumes. Auxiliary volumes can be located on the same system or located on another system. For auxiliary volumes on a different system, a partnership must also be created between the systems. Click Next
Select the master and auxiliary volumes for the remote-copy relationship. Click Add after each pair of volumes in the relationship.
Select whether change volumes are added to the primary and auxiliary volumes for the relationship. Change volumes use track updates to the primary and auxiliary volumes and make copy operations faster and more efficient. Change volumes are selected by default. Click Next.
Select whether volumes are already synchronized. Click Next.
Select whether to start a copy operation between the selected immediately or wait until after the relationship is created and click Finish.

Using the CLI

To create an IP partnership, complete these steps:

Create a portset

To create a portset, enter the following command:
```
mkportset -name portset_name -type portset_type -ownershipgroup owner_name
```
where portset_name is the name of the portset and portset_type is replication. The value owner_name indicates the name of the ownership group to which the portset belongs. It is an optional value.
After creation of the portset for the traffic type, enter the following command to assign IP addresses to the portset:
```
mkip -node <id | name> -port <id> -portset <id | name> -ip <ip address> -prefix <subnet prefix> -gw <gateway address> -vlan <vlan_id> 
```
where id | name is the name or ID of the node; id is the port identifier; and id | name indicates the name or ID of the portset that was created earlier. Enter either a valid IP address for the -ip and include the values for the address. This address that is assigned to the portset and more addresses can be added to portset with the mkip command.
After you assign the IP addresses to portset, you can assign the portset to the new IP partnership.

Create partnership

To add a portset to a new IP partnership, enter the following command:

To verify that the portset type is the replication for an IP partnership, enter the following command:
```
lsportset
```
In the results that display, verify and that the portset_type is replication. You can assign an IP partnership to a portset with the replication type.
If you are creating a partnership between systems that are connected through one inter-site link, enter the following command on the local system:
```
mkippartnership -type ipv4 -clusterip x.x.x.x -linkbandwidthmbits 1000 -backgroundcopyrate 50 -link1 myportset1               
        
```
Note: To have a fully configured partnership, repeat the preceding command on the remote system.
If you are creating a partnership between systems that are connected through dual inter-site links, enter the following command on the local system:
```
mkippartnership -type ipv4 -clusterip x.x.x.x -linkbandwidthmbits 1000 -backgroundcopyrate 50 -link1 myportset1 -link2 myportset2            
        
```
Note: To have a fully configured partnership, repeat the preceding command on the remote system.

After you complete all these steps, run lspartnership command on each system in the configuration and verify the following items:

Portsets are configured for all links between the systems.
All systems are in the Fully Configured state.

After confirming that the partnership is configured, you can configure a remote-copy relationship between the volumes in the production systems to auxiliary volumes that are located on remote systems. There are three types of replication remote-copy relationships that you can create:

Metro Mirror

To create a Metro Mirror relationship, enter the following command:

mkrcrelationship -master volumeA -aux volumeB -cluster remotecluster -name myrel -metro

Global Mirror

mkrcrelationship -master volumeA -aux volumeB -cluster remotecluster -name myrel -global

Global Mirror with Change Volumes

mkrcrelationship -master volumeA -aux volumeB -cluster remotecluster -name myrel -global -cyclingmode multi