Features and Benefits of HSG80 ACS 8.6P Data Replication Manager

Features and Benefits of HSG80 ACS 8.6P Data Replication Manager 16
DRM Dual Switch/Single Site Configuration
Compaq supports the DRM Dual Switch/Single Site configuration for those environments that
only need local data protection in the event of local disasters or that are used as local test beds for
operational DRM solutions. This solution uses only two switches, where each switch creates a
fabric “in a box” instead of the multiswitch fabrics supported in the non-Dual Switch/Single Site
DRM solutions.
The Compaq Storage Solutions team has created the Departmental DataSafe solution for those
customers requiring a turnkey data protection solution that is based on Windows 2000 or
Windows NT. More information on the Departmental DataSafe solution is available at
www.compaq.com/products/storageworks/solutions/essa/deptdatasafe.html
Because of its design, a DRM Dual Switch/Single Site is limited to supporting one “switch
worth” of connections (8 or 16 ports). Therefore, given a DRM Dual Switch/Single Site
consisting of two 16-port switches, the maximum configuration is one of the following:
• Twelve servers and 1 pair of arrays
• Eight servers and 2 pairs of arrays
• Four servers and 3 pairs of arrays
The maximum DRM Dual Switch/Single Site configuration is slightly larger than the DRM-to-
ATM configuration because there is no intersite link filling the sixteenth port like there is in the
DRM over ATM solution.
The HSG80 and the server HBA use only shortwave GBICs. This means that the DRM Dual
Switch/Single Site configuration is limited to 500 meters of 50 micron or 200 meters of
62.5 micron multi-mode fiber optic cable between the HBA and either switch and between the
controller and either switch. This limits the DRM Dual Switch/Single Site to a maximum
separation of 1 km using 50 micron cable (400 meters with 62.5 micron cable) between primary
and alternate servers and primary and alternate storage arrays.
To achieve this maximum distance, Compaq recommends locating the two switches somewhere
between the primary site and the alternate site. Both switches should be installed in separate
locations with unique fiber paths between the switch and both sites. For example, a single
backhoe will not cut both fabrics isolating the primary and alternate sites from each other. The
DRM Dual Switch/Single Site is not designed to survive large area natural disasters such as
tornadoes, earthquakes, or hurricanes because of the limited intersite distance. The DRM Dual
Switch/Single Site may not survive or continue to operate after two unrelated failures due to its
limited NSPOF configuration.