IBM System storage DS6000 Series Redbook page 499

Local DS6000 / DS8000
Session
1
Local DS6000 / DS8000
Session
2
Figure 31-6 TPC for Replication - Session concept
Metro Mirror primary volume P1 in the second storage server and volumes P2 and P3 in the
first storage server with their corresponding Metro Mirror secondary volumes are grouped
together in a session, session 1. Such a session can contain Copy Sets that span storage
server boundaries.
Metro Mirror primary volumes PA and PB with their counterparts at the remote site belong to
a different session, session 2.
Note that all application-dependent Copy Sets must belong to the same session to guarantee
successful management and to provide consistent data across all involved volumes within a
session. In this context it is recommended to have application-dependent volume granularity
within the scope of an LSS. Or, in other words, volumes or Copy Sets that require consistent
data and can be subject to a freeze trigger ought to be grouped in one or more LSS and that
LSS must not contain other Copy Sets. This is because the scope of the freeze function is at
the LSS level and affects all volumes within that LSS.
A
P3
PPRC path
Primary
Primary
Primary
A
P2 PPRC path
Primary
Primary
Prim ary
A
PPRC path
Primary
P1
Primary
Primary
A
PPRC path
Primary
PB
Primary
Primary
A
PPRC path
Primary
PA
Primary
Primary
Local site
Chapter 31. IBM TotalStorage Productivity Center for Replication
Remote DS6000 / DS8000
S3
Copy Set
Secondary
Copy Set
S2
Secondary
Remote DS6000 / DS8000
A
Primary
Copy Set
Primary
S1
Primary
Secondary
A
Primary
Copy Set
Primary
SB
Primary
Secondary
A
Primary
Copy Set
Primary
SA
Primary
Secondary
Remote Site
475