EMC VMAX 100K - Srdf;Star Solutions; Cascaded SRDF Topology

Figure 19 Cascaded SRDF topology
SRDF/A or
Adaptive copy
Site A
Host
Site B Site C
R1
R2
SRDF/S,
SRDF/A or
Adaptive copy
R21
SRDF/Star solutions
SRDF/Star is a disaster recovery solution that consists of three sites; primary
(production), secondary, and tertiary. The secondary site synchronously mirrors the
data from the primary site, and the tertiary site asynchronously mirrors the production
data.
Note
In mainframe environments, GDDR is required to implement SRDF/Star. For more
information, refer to the appropriate GDDR product guide.
In the event of an outage at the primary site, SRDF/Star allows you to quickly move
operations and re-establish remote mirroring between the remaining sites. When
conditions permit, you can quickly rejoin the primary site to the solution, resuming the
SRDF/Star operations.
SRDF/Star operates in concurrent and cascaded environments that address different
recovery and availability objectives:
l
Concurrent SRDF/Star — Data is mirrored from the primary site concurrently to
two R2 devices. Both the secondary and tertiary sites are potential recovery sites.
Differential resynchronization is used between the secondary and the tertiary
sites.
l
Cascaded SRDF/Star — Data is mirrored first from the primary site to a
secondary site, and then from the secondary to a tertiary site. Both the secondary
and tertiary sites are potential recovery sites. Differential resynchronization is
used between the primary and the tertiary site.
Differential synchronization between two remote sites:
l
Allows SRDF/Star to rapidly reestablish cross-site mirroring in the event of the
primary site failure.
l
Greatly reduces the time required to remotely mirror the new production site.
In the event of a rolling disaster that affects the primary site, SRDF/Star helps you
determine which remote site has the most current data. You can select which site to
operate from and which site’s data to use when recovering from the primary site
failure.
If the primary site fails, SRDF/Star allows you to resume asynchronous protection
between the secondary and tertiary sites, with minimal data movement.
SRDF/Star for open systems
Solutions Enabler controls, manages, and automates SRDF/Star in open systems
environments. Session management is required at the production site.
Remote replication solutions
SRDF/Star solutions 109