Cautions On Using Compatible Super Pav - HPE XP7 User Manual

• Increase in the processor availability ratio and delay in the associated I/O processing (increase in the
amount of queuing time and response time).
• Suspend due to full journal volume caused by data inflow increase.
• Overload of the connection path between the primary and secondary storage systems.
In particular, in a system that contains a CU (a CU with a high IOSQ at all times) in which alias volumes
are always depleted, using Compatible Super PAV causes the increase in the load on the system, and
therefore the system balance might be lost. Make sure that there are no high load portions (such as the
processor availability ratio or the path between the primary and secondary storage systems) before
enabling Compatible Super PAV.
When Compatible Super PAV is newly installed, we recommend to define required alias volumes in its CU
as with Hyper Parallel Access Volumes. Alias volumes are grouped into even numbered CUs and odd
numbered CUs, and only aliases in the same group can be shared. Therefore, make sure to design the
appropriate number of alias volumes in order to avoid being biased by considering the number of base
volumes in even numbered CUs and odd numbered CUs, and the assumed multiplicity.
In the configuration where the number of alias volumes in its CU is minimized and alias volumes are
collectively defined in several CUs as pools, many I/Os use alias volumes in different CUs. In this case,
you cannot manage how the host computer assigns alias volumes to many I/O operations to be
performed. Therefore, we recommend to design alias volumes as much as possible based on the
operations with Hyper Parallel Access Volumes to avoid the complicated performance design.

Cautions on using Compatible Super PAV

When Compatible Super PAV is enabled using Remote Web Console, the following cautions are required.
Operations in storage system
If the following operations are performed in the storage system, a host computer might not recognize all
alias volumes:
• Deleting alias volumes which are online.
• Turning off the power while JOB is running.
If alias volumes are not recognized, take the corrective actions to enable Compatible Super PAV. To make
sure that alias volumes are recognized, issue the following commands on the terminal of the host
computer:
ds qpav, bbbb(base volume), volume
The following is an output example of the status that alias volumes are recognized.
DS QP,EE66,VOL
IEE459I 21.57.57 DEVSERV QPAVS 789
HOST
CONFIGURATION
---------------
UNIT
NUM. UA TYPE
----- -- ----
0EE66 C6 BASE-H
1EE30 F0 ALIAS-H
1EE6F EF ALIAS-H
**** 3 DEVICE(S) MET THE SELECTION CRITERIA
16 Cautions on using Compatible Super PAV
SUBSYSTEM
CONFIGURATION
---------------------
UNIT
STATUS SSID ADDR.
------ ---- ----
7AF3 C6
7AF1 F0
7AF3 EF
UA
TYPE
----------
BASE