HP StorageWorks SAN Virtualization Services Platform administrator guide (5697-0204, January 2010)

10 Site failure recovery with synchronous
mirroring
The Virtualization Services Manager (VSM) synchronous mirroring feature provides continuous access
to a virtual disk even if one of the underling physical storage component fails. Synchronous mirroring
is done with the local domain only, but can be two sites as in a stretched domain. VSM further
enhances the synchronous mirroring capabilities by enabling continuous access to a virtual disk that
has experienced multiple failures, such as an all-site failure, by using the new Force Resume and Force
Delete features. This chapter explains how and when to use the new Force Resume and Force Delete
features.
Synchronous mirroring across SVSP sites
Figure 34 shows synchronous mirroring across SVSP sites with stretched DPMs. The domain has two
sites constructed with two dedicated DPMs (DPM 1 and DPM 2) for running synchronous mirrors
across the sites. The sites are organized in a redundant configuration that consists of a storage array,
which has redundant controllers and host ports, two fabrics, two VSM servers, and host servers with
two HBAs. The fabrics of the sites are interconnected to form two fabrics, which are shown as blue
fabric and the red fabric.
Figure 34 Synchronous mirroring across sites with stretched DPMs
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