IBM System storage DS6000 Series Redbook page 310

FCQUERY Formatted -2
DEVN SSID LSS CCA CU
6403 0002 00 03 1750 0000000AAVCA
FCQUERY COMMAND COMPLETED FOR DEVICE 6403. COMPLETION CODE: 00
Example 23-5 shows, for each single FlashCopy relationship, a column titled RV, which stands
revertible
for
are committed. All volumes show the same information for RV. The other column that you have
to check is the SEQNUM or FlashCopy sequence number. This number is also identical for all
four volumes in Example 23-5, which is good information. This leads you to conclude that:
All FlashCopy pairs are non-revertible.
All FlashCopy sequence numbers are equal.
No further action is necessary and the set of C volumes is consistent and a good copy.
Figure 23-13 shows the consistency group creation process. The action required depends on
the state of the consistency group creation process when the failure occurred.
Create consistency group by holding
application writes while creating
bitmap containing updates for this
consistency group on all volumes -
design point is 2-3ms
Maximum coordination time (eg. 10ms)
Figure 23-13 FlashCopy consistency group creation process
Depending on when the failure occurs, there are some combinations of revertible states and
FlashCopy sequence numbers that need different corrective actions. Use Table 23-1 as a
guide. This is a decision table that is read in the following way: When column 2
are true, then take the action in column 4. Column 5 contains additional comments. Do this
for each of the four cases. The cases are described in chronological order, starting from the
left.
Table 23-1 Consistency Group and FlashCopy validation decision table
Are all FC
relationships
revertible?
Case 1 NO.
286
IBM System Storage DS6000 Series: Copy Services with IBM System z
SERIAL
. An N indicates that this FlashCopy relationship is not revertible and all changes
FlashCopy issued
with revertible option
Drain consistency group and send
to remote DS using Global Copy.
Application writes for next
consistency group are recorded in
change recording bitmap
Maximum drain time – eg.1 min
Are all FC sequence
numbers equal?
YES.
ACT MAX XC PC CC RV SEQNUM
1 50099 N S N N 42B03957
Transmit updates in Global Copy mode
while between consistency groups
Consistency group interval – 0s to 18hrs
All FlashCopies
revertible
Start next consistency group
FlashCopy committed
once all revertible
Flashcopies have
successfully completed
Action required
Action to take
No action needed. All
C volumes are
consistent.
and
column 3
Comments
CG formation ended.