IBM SG24-5360-00 Manual Do Utilizador
Chapter 5. Peer-to-Peer Remote Copy
In this chapter we describe the VSE/ESA support for the RVA and the PPRC.
As part of the continuing effort to meet customer requirements for 24-hour 7-day
availability, the RVA Model T82 provides remote copy for disaster and critical
volume protection. PPRC is supported by OS/390, VSE/ESA, and VM/ESA. PPRC
complements the existing availability functions of the RVA, such as the dual
power systems, nonvolatile storage (NVS), and nondisruptive installation and
repair.
availability, the RVA Model T82 provides remote copy for disaster and critical
volume protection. PPRC is supported by OS/390, VSE/ESA, and VM/ESA. PPRC
complements the existing availability functions of the RVA, such as the dual
power systems, nonvolatile storage (NVS), and nondisruptive installation and
repair.
PPRC standardizes and streamlines today
′
s disaster recovery data backup
capabilities by providing data-type independent remote copy. The
implementation provides a choice based on business requirements such as
performance needs, data synchrony criteria, system resource considerations,
operational control requirements, and recovery distance requirements.
implementation provides a choice based on business requirements such as
performance needs, data synchrony criteria, system resource considerations,
operational control requirements, and recovery distance requirements.
PPRC provides an RVA synchronous data copying capability for protection
against loss of access to data in the event of an outage at the primary site.
Updates are sent from the primary RVA directly to the recovery RVA in a cache
to cache communication through dedicated ESCON links between the two RVAs.
The RVA can be located up to 43 km (26.7 mi) from the host. The primary and
secondary volumes must be of the same track geometry.
against loss of access to data in the event of an outage at the primary site.
Updates are sent from the primary RVA directly to the recovery RVA in a cache
to cache communication through dedicated ESCON links between the two RVAs.
The RVA can be located up to 43 km (26.7 mi) from the host. The primary and
secondary volumes must be of the same track geometry.
Figure 19 shows two host systems with an RVA attached to each. The two RVAs
are attached on at least one ESCON path. ESCON Directors can be used to
extend the distance between the two hosts up to 43 km. The second host is
optional if PPRC is being used to migrate data from one RVA to a second within
the same data center.
are attached on at least one ESCON path. ESCON Directors can be used to
extend the distance between the two hosts up to 43 km. The second host is
optional if PPRC is being used to migrate data from one RVA to a second within
the same data center.
Figure 19. Peer-to-Peer Remote Copy
Both RVAs can treat writes as DASD fast write (DFW) operations. The primary
RVA write is handled normally, and it is processed as a cache hit whenever
possible; the write to the secondary subsystem is always treated as a write hit.
This capability, and the inherent performance capabilities of the RVA, help to
mitigate the unavoidable performance impacts of writing the data to both RVAs
before signaling the operation as complete to the primary host application.
RVA write is handled normally, and it is processed as a cache hit whenever
possible; the write to the secondary subsystem is always treated as a write hit.
This capability, and the inherent performance capabilities of the RVA, help to
mitigate the unavoidable performance impacts of writing the data to both RVAs
before signaling the operation as complete to the primary host application.
Copyright IBM Corp. 1999
33