Features and Benefits of HSG80 ACS 8.6P Data Replication Manager

Features and Benefits of HSG80 ACS 8.6P Data Replication Manager 12
An association set can have up to 12 remote copy set members. All members of an association set
must be on the same fabric to maintain controller cache coherency. When members are added to
an association set, they are moved to the same initiator controller and fail over together. A
maximum of 12 association sets, one per RCS, are available per pair of storage arrays running in
DRM mode.
Basic DRM Configuration
The cabling in this configuration supports two redundant fabrics. As shown in Figure 5, the first
HBA in Host A is connected to Switch C, which belongs to Fabric A. The second HBA in Host A
is connected to Switch D, which belongs to Fabric B.
This dual-fabric SAN provides NSPOF at the fabric level. For example, broken cables, switch
updates, or an error in switch zoning can cause one fabric to fail, leaving the other to temporarily
carry the entire workload.
Host A
Switch C
Switch D
Fabric A
Host W
Switch Y
Switch Z
Fabric B
Initiator
Target
Figure 5: Basic DRM configuration
The allowable distance between the initiator and target depends on the cabling and GBIC used for
the intersite links. A shortwave GBIC supports distances up to 500 meters with 50-micron
multimode cable and 200 meters with 62.5-micron multimode cable. A longwave GBIC with
single mode fiber supports distances up to 10 km (6.2 miles). A Very Long Distance GBIC or
WDM supports intersite links up to 100 km (62 miles). As shown in the next two examples, DRM
over ATM or DRM over IP is available for even longer distances or for those environments
where fiber optic cable is available between two sites.
Long Distance Solutions
The following configurations explain how to use DRM over long distances.
Extended DRM over ATM Configuration
The extended DRM over ATM configuration is similar to the simple DRM configuration except
for the use of Fibre Channel-to-ATM gateways from CNT Corporation. In this example a second
server has been added at each site showing support for local clusters or different but compatible
(at the storage level) operating systems. As shown in Figure 6, two FC-to-ATM gateways are
required at each site, one for each fabric.