Filter
Top Products
Chapter 2 Data Replication
14
2
2
2
.
.
.
3
3
3
.
.
.
2
2
2
S
S
S
e
e
e
p
p
p
a
a
a
r
r
r
a
a
a
t
t
t
e
e
e
a
a
a
n
n
n
d
d
d
S
S
S
t
t
t
a
a
a
t
t
t
e
e
e
T
T
T
r
r
r
a
a
a
n
n
n
s
s
s
i
i
i
t
t
t
i
i
i
o
o
o
n
n
n
s
s
s
When Separate is performed, the difference between MV and RV at the time of executing the Separate
start instruction is reflected to RV and RV is separated. No update to MV after Separate is reflected to
RV.
After Separate is performed, data copy to RV is performed if the contents of MV and RV at the
beginning of Separate do not match, and all updates to MV before the Separate start instruction are
reflected to RV. The state from the beginning of Separate to the content of MV at the beginning of
Separate is completely reflected to RV is called the “Separate execution state“. The state where all
updates to MV are reflected to RV is called the state separated by Separate, or the “separated state“.
Separate execution and the separated state are collectively called the Separate state.
When Separate is executed under specification of immediate use of RV (Separate(immediate)), the RV
contents can be referred to or updated immediately after the Separate start instruction is issued,
regardless of whether or not all the MV contents have been reflected into the RV. This feature is
implemented as follows.
When an update/reference request for the RV is made and access to an area where difference copy from
the MV into RV is not completed is to be made, control is performed for copying the difference from
the MV into RV before permitting access to the area.
The updates made to MV until Separate is started are reflected to RV. The updates made to MV after
Separate is started are not reflected to RV and managed as update difference.
The updated states of MV and RV are managed in Separate State so that the difference between the MV
and RV contents is reflected when Replicate/Restore is executed.
Figure 2-4 Separate and State Transitions
MV
RV
MV
RV
MV
Update to MV
Update to MV
Update to MV
Synchronous State
RV
Separate Execution
Separated State
Separate State
Separate
operation starts
Until the difference
between MV and
RV is fully reflected
to RV