You can configure IBM Spectrum Virtualize 3-Site Orchestrator to manage
replications in both remote-copy configurations and in HyperSwap configurations. Both configurations
define sites and links between each site.
Each site can operate as either the Primary,
Master, Auxiliary Near (Aux-Near), or Auxiliary Far
(Aux-Far). These sites are defined slightly differently depending on whether you are
configuring 3-site replication with Metro Mirror configurations or configuring HyperSwap® system with disaster recovery at a third site. The
Comparison of site
definitions provides an overview of these differences.
Site
Metro Mirror configuration
HyperSwap configuration
Primary
The primary site is the site from which data is replicated to two alternative sites. In a
Metro Mirror configuration, the primary site can be changed based on outage. Usually the master site
is the primary site; however, if the master site experiences an outage, administrators can switch
application I/O and replication can shift to other systems on alternative sites.
With HyperSwap configurations, the primary site
is automatically set since both sites in a HyperSwap
configuration receive application I/O. The primary site receives I/O for a particular consistency
group.
Master
The master site is added to the configuration first and the identifies automatically as the
master site. The system at that site that is selected during configuration and is identified by
unique management IP addresses.
The master site is one of the near sites in the HyperSwap system. In a HyperSwap system, I/O
groups are configured at separated locations. The 3-Site Orchestrator always identifies the master
site as site ID 1, but master and auxiliary near sites use the same management IP addresses and
system name.
Auxiliary-Near
One of the near sites in 3-site configuration. This system is selected during configuration
and has unique management IP addresses.
The distance between the master site and the
auxiliary-near site must not exceed 300 km.
For HyperSwap configurations, the auxiliary-near
site is one of the near sites in the HyperSwap system.
The always identifies the auxiliary-near site as Site ID 2, but master and auxiliary near sites
use the same management IP addresses and system name.
The distance between the master site and
the auxiliary-near site must not exceed 300 km.
Auxiliary-Far
The system at the auxiliary-far site is the target for the asynchronous copy of the data from
either the master site or the auxiliary-near site.
The auxiliary-far site is typically 100s of km
or more from the near sites.
The system at auxiliary-far site is the target for the asynchronous copy of the data on the
HyperSwap system at near sites.
The auxiliary-far
site is typically 100s of km or more from the near sites.
Quorum site
NA
Quorum management is used in HyperSwap
configurations. You either specify a site for quorum disk management or use an IP quorum
application to manage a quorum disk that is used in tie-break situations.
Near sites
This term is used to describe the master and auxiliary sites.
This term describes the master and auxiliary sites refers to the sites on which the HyperSwap system is configured.
In addition, the master and auxiliary-near sites are connected to the auxiliary-far site
through an active link and a standby link.
Active Link
The link to the auxiliary-far site from the master site or auxiliary-near site that is
responsible for asynchronous replication of the data between the sites (periodic replication).
Standby Link
The link is in an idle copy state. The link is available when an active link fails.
Topologies for IBM Spectrum Virtualize 3-Site Orchestrator with Metro
Mirror configurations
Topologies define how data is replicated and managed by IBM Spectrum Virtualize 3-Site Orchestrator. For remote copy configurations, the
sites can be configured into either a Cascade or Star topology.
Cascade Topology
When a cascade topology is configured, the primary site replicates data to the partner-near site
which in turn replicates data to the auxiliary-far site.
The cascade topology
distributes the workload evenly between a production system and local-replication system.Figure 1 illustrates the cascade
topology. Figure 1. Cascade topology
Star Topology
When a star topology is configured, the primary site replicates data to both the partner-near
site (auxiliary-near site in this example) and auxiliary-far site.
Figure 2 illustrates the star
topology. Figure 2. Star Topology
Topologies for IBM Spectrum Virtualize 3-Site Orchestrator with
HyperSwap configurations
For HyperSwap configurations with IBM Spectrum Virtualize 3-Site Orchestrator, the following topologies are
supported:
Figure 3 shows a 3-Site
Orchestrator topology in which the primary site replicates data to the partner-near site, which in
turn replicates data to the auxiliary-far site. The active links are shown as green lines and the
standby link is shown as a yellow line.Figure 3. Primary site replicates data
to the auxiliary-near site
Figure 4 shows a IBM Spectrum Virtualize 3-Site Orchestrator topology
in which the primary site replicates data to both the partner-near site and the auxiliary-far site.
The active links are shown as green lines and the standby link is shown as a yellow line.Figure 4. Primary site replicates data to the auxiliary-near site and the
auxiliary-far site