HyperSwap system configuration details

You can create an IBM® HyperSwap® topology system configuration where each control enclosure that is used to access a HyperSwap volume is physically on a different site. When used with active-active relationships to create HyperSwap volumes, these configurations can be used to maintain access to data on the system when power failures or site-wide outages occur.

In a HyperSwap configuration, each site is defined as an independent failure domain. If one site experiences a failure, then the other site can continue to operate without disruption. You must also configure a third site to host a quorum device or IP quorum application that provides an automatic tie-break in case of a link failure between the two main sites. The main site can be in the same room or adjacent rooms in the data center, buildings on the same campus, or buildings in different cities. Different kinds of sites protect against different types of failures.

Sites are within a single location: If each site is in a different power phase within a single location or data center, the system can survive the failure of any single power domain. For example, one node can be placed in one rack installation and the other node can be in another rack. Each rack is considered a separate site with its own power phase. In this case, if power was lost to one of the racks, the partner node in the other rack might be configured to process requests. The partner node can effectively provide availability to data even when the other node is offline due to a power disruption.
Each site is at separate locations: If each site is in a different physical location, the system can survive the failure of any single location. These sites can span shorter distances, for example two sites in the same city, or they can be spread farther geographically, such as two sites in separate cities. If one site experiences a site-wide disaster, the remaining site can remain available to process requests.

If configured properly, the system continues to operate after the loss of one site. The key prerequisite is that each site contains one of the control enclosures that are used to access copies of the HyperSwap volume. In the management GUI, the Modify System Topology wizard simplifies setting up HyperSwap system topology. After you configure HyperSwap topology, you can use the Create Volumes wizard to create HyperSwap volumes and copies for each site. In addition, the HyperSwap volume wizard automatically creates active-active relationships and change volumes to manage replication between sites. If you are configuring HyperSwap by using the command-line interface, you must also configure the system topology, volumes, and active-active relationships separately.

The system supports both Fibre-Channel and Ethernet connections between nodes with a stretched system. Ethernet connections are only supported through RDMA-capable adapters that must be installed and configured on each node within the HyperSwap system.

HyperSwap system configurations support both Fibre Channel and Ethernet (iSCSI or iSER) host attachment; however, host attachment with NVM Express (NVMe) over Fibre Channel is not supported for HyperSwap systems.