HP XP Racks - Manual (Page 8)

Typical components
A typical configuration consists of the following components. Many but not all require user setup.
•
The primary XP7 storage system is connected to a host. The secondary storage system is
connected to the primary system via Fibre Channel data paths. The secondary system may be
XP7, other HP model, or a third-party storage system.
•
A host at the local site, connected to the primary storage system. It is also highly desirable to
have a host at the secondary site connected to the secondary system for use in a disaster
recovery. If this is not possible, the local host must be in communication with the secondary
system.
•
A P-VOL on the primary storage system that is copied to the S-VOL on the secondary system.
The P-VOL and S-VOL may be composed of expanded LUs using LUN Expansion.
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Fibre Channel data paths for data transfer between primary and secondary system.
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Target, initiator, and RCU target ports for the Fibre Channel interface.
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Remote Web Console graphical user interface software, used to perform Continuous Access
Synchronous configuration and pair operations. RAID Manager software may also be used
for most pair operations and disaster recovery operations.
The following figure shows a typical Continuous Access Synchronous environment.
Storage systems
Continuous Access Synchronous operations take place between the primary XP7 system and the
secondary system, which can be another XP7 Storage, P9500, or XP24000/XP20000 Disk Array.
The primary system manages the P-VOL and the following operations:
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Host I/O operations to the P-VOL.
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Initial copy and update copy operations between the P-VOL and S-VOL.
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Pair status and configuration information.
The secondary system manages the S-VOL and the following operations:
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Secondary copy operations issued by the primary system.
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Assists in managing pair status and configuration (for example, rejects write I/Os to the S-VOL).
The primary system communicates with the secondary system over dedicated Fibre Channel data
paths.
The XP7 CU can function simultaneously as a primary system for one or more P-VOLs, and as a
secondary system for one or more S-VOLs. This kind of configuration requires that data paths and
Fibre Channel ports are configured for both copy directions.
8 Continuous Access Synchronous overview