HP XP Racks - Manual (Page 16)

3 x 10 + 577 x 20 = 11,570 <= 57,600
and
1 x 10 + 17 x 20 = 350 less-than-or-equal-to 8,192
Thus, you can create 10 BC pairs of OPEN-3 volumes and 20 BC pairs of OPEN V volumes.
Quick Split and Steady Split performance planning
The following dependencies affect the performance of pairs that are in the process of Quick Split
(“PSUS(SP)/PSUS” status) or Steady Split (“COPY(SP)/COPY” status):
•
The system option mode (SOM) 459 is ON.
•
The S-VOL is an external or internal volume.
•
The S-VOL is a volume that is part of a THP V-VOL.
The following table shows the affects of these conditions.
PSUS(SP)/PSUS or COPY(SP)/COPY status S-VOL SOM 459
Differential data is copied to the cache in the XP7 storage system.
The pair is in the process of Quick Split (“PSUS(SP)/PSUS” status). Internal volume OFF
External volume
Internal volume ON
Differential data is copied to the cache in the XP7 storage system and
destage to the external storage system has completed. The pair is split
(“PSUS” status). External volume
* Indicates a THP V-VOL.
Related topics
•
“Splitting BC pairs” (page 48) .
•
“Pair splitting methods” (page 46) .
Performance planning and calibrating your XP7 storage system
Performing pair tasks, such as creating, splitting, and resynchronizing BC pairs, affect host server
I/O performance on the XP7 storage system. Calibrate your XP7 storage system before performing
tasks.
You can also maximize host server I/O performance.
For more information about the guidelines for maximizing host server I/O performance, see
“Guidelines for maximizing host server I/O performance” (page 17) .
The following is a list of items you can complete to calibrate your system:
•
Host server I/O performance versus number of BC pairs. Compare the importance of host
server I/O performance with the number of BC pairs and the copy pace.
Assigning multiple S-VOLs to a P-VOL uses more system resources and lowers performance.
•
Load sharing on parity groups.
Assign S-VOLs to newly installed parity groups. Overloading the XP7 storage system
increases parity groups, cache, channel adapters (CHAs), and/or disk adapters (DKAs). ◦
◦ Evenly distribute the P-VOLs and S-VOLs in the parity group, rather than containing a
concentration of one or the other.
16 Business Copy system requirements and planning