HP XP Racks - Manual (Page 54)

There are five types of 3DC configurations:
•
3DC Cascade (Cnt Ac-S Z x Cnt Ac-J Z) configuration
•
3DC Cascade (Cnt Ac-J Z x Cnt Ac-J Z) configuration
•
3DC Multi-Target (Cnt Ac-S Z x Cnt Ac-J Z) configuration
•
3DC Multi-Target (Cnt Ac-J Z x Cnt Ac-J Z) configuration
•
Delta Resync configuration
3DC (Cnt Ac-J Z x Cnt Ac-J Z) configuration is a generic term used to refer to 3DC Cascade (Cnt
Ac-J Z x Cnt Ac-J Z) configurations and 3DC Multi-Target (Cnt Ac-J Z x Cnt Ac-J Z) configurations.
Table 11 (page 54) provides an overview of the 3DC configurations. Select the configuration that
is most appropriate to your needs.
Table 11 Overview of each 3DC configuration
Characteristics Connection type Configuration name
Primary → Intermediate (nearby) → Remote
(distant)
3DC Cascade (Cnt
Ac-S Z x Cnt Ac-J Z)
configuration •
Because data is remotely copied through
the intermediate site, the remote site can
be at a more distant place.
• Cnt Ac-S Z x Cnt Ac-J Z: Because
Continuous Access Synchronous Z
Primary → Intermediate (distant) → Remote
(distant)
3DC Cascade (Cnt
Ac-J Z x Cnt Ac-J Z)
configuration
performs operations from the primary site
to the intermediate site, the updating of
data between the two sites is essentially
instantaneous.
•
Cnt Ac-J Z x Cnt Ac-J Z: Because
Continuous Access Journal Z performs
operations from the primary site to the
intermediate site, the I/O load on the host
is low.
Primary
→ Local (nearby)
3DC Multi-Target
(Cnt Ac-S Z x Cnt • Because the data can be remotely copied
from the primary site to two sites at the
Primary
→ Remote (distant)
Ac-J Z)
configuration
same time without using an intermediate
site, the time lag between sites is low.
• If a disaster occurs at a site other than the
primary site, the configuration can be
changed to a 2DC configuration by
Primary → Remote 1 (distant) 3DC Multi-Target
(Cnt Ac-J Z x Cnt
performing a remote copy between the
remaining sites.
Primary → Remote 2 (distant)
Ac-J Z)
configuration
• Cnt Ac-S Z x Cnt Ac-J Z: Because
Continuous Access Synchronous Z
performs operations from the primary site
to the local site, the updating of data
between the primary site and the local site
is essentially instantaneous.
• Cnt Ac-J Z x Cnt Ac-J Z: Because
Continuous Access Journal Z performs
operations from the primary site to both
remote sites, the I/O load on the host is
low.
In addition to the characteristics of 3DC
Multi-Target (Cnt Ac-S Z x Cnt Ac-J Z) Primary
→ Local (nearby) 1
Primary → Remote (distant) 1
Delta Resync
configuration
configurations, if a storage system failure
occurs at the primary site, the configuration
can be changed to a 2DC configuration by
performing a Delta Resync (which copies only
differential data).
54 Business Continuity Manager with replication products