HP XP7 Storage User Manual
Page 28
When data is sent to the secondary systems, the systems check time stamps, which are added
when data is written by the hosts to the P-VOLs. The secondary systems then restore the data to the
S-VOLs in chronological order (older data are restored earlier). This ensures that the update sequence
is maintained.
Note the following when planning for multiple systems:
•
Remote Web Console is required at the primary and secondary sites.
•
RAID Manager is required on the host at the primary and secondary sites.
•
Journal data is updated in the secondary system based on the time stamp issued from RAID
Manager and the sequence number issued by the host with write requests to the primary
system. Time and sequence information remain with the data as it moves to the master and
restore journals and then to the secondary volume.
•
With RAID Manager consistency groups, when a pair is split from the S-VOL side (P-VOL status
= PAIR), each storage system copies the latest data from the P-VOLs to the S-VOLs. P-VOL time
stamps might differ by storage system, depending on when they were updated.
•
Disaster recovery can be performed with multiple storage systems, including those with Cnt
Ac-J and Cnt Ac-J Z journals, using RAID Manager. See
“Switching host operations to the
for information
•
An error in one journal can cause suspension of all journals. See
for more information.
•
Time stamps issued by RAID Manager and the mainframe host are different. The time stamps
issued by the mainframe host become invalid when the Cnt Ac-J Z journal is included in a
RAID Manager consistency group.
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Planning volumes, XP7 systems