HP StorageWorks SAN Virtualization Services Platform administrator guide (5697-0109, July 2009)

8 Synchronous mirroring in a single
stretched domain
The SAN Virtualization Services Platform solution supports mirroring over a stretched distance as
shown in Figure 25. This configuration is interesting because of the opportunities for different failure
domains that the distance affords.
Solution topology
Figure 25 shows the topology of a synchronous mirror configuration in a single SVSP domain with
two SVSP sites. Figure 25 shows two sites that represent two independent data centers. Each site is
organized in a redundant SAN configuration and includes:
• At least one storage array with redundant controllers
• Two fabrics
• One VSM server
• One Data Path Module (DPM) per DPM group
• Servers, with each server having at least two host bus adapters (HBAs)
The fabrics of the two sites are interconnected to form two “cross-site fabrics.” The cross-site fabrics
are indicated by the blue and the red lines in Figure 1.
Figure 25 Synchronous mirroring in one stretched domain
Configuration requirements
The setup virtual disk of the domain is synchronously mirrored with up to five tasks, including the
original virtual disk. While the requirement is to have at least one synchronized task of the setup
virtual disk on each site, best practice has at least two setup volumes per site. This allows the active
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