Planning For Performance - HP XP P9500 User Manual

Table 5 Volume information for Business Copy (continued)
CU Port
0 2A
0 2A
etc... NA
0 3A
0 3A

Planning for performance

Pair operations affect I/O performance on the storage system. The following information is provided
to help calibrate your system:
Performance versus number of pairs. Compare the importance of performance with the number
of pairs and copy pace (rate at which data is copied).
Assigning multiple S-VOLs to a P-VOL uses more system resources and lowers performance.
◦
◦ The slower the copy pace, the less impact on I/O performance; a fast pace has a greater
impact on performance. (You assign copy pace during the create, split, and resync
operations.)
Load sharing on parity groups.
◦ A parity group should contain an even distribution of P-VOLs and S-VOLs, rather than a
concentration of one or the other.
◦ When multiple pair operations are to be performed simultaneously, the pairs should be
in different parity groups.
For copy pace, specify Slower when you create, split, or resynchronize.
◦
When you need to perform a copy operation on multiple pairs on the same parity group,
◦
perform the operation on one pair at a time.
If the system is overloaded, increase parity groups, cache, channel adapters (CHAs),
◦
and/or disk adapters (DKAs). Assign S-VOLs to newly installed parity groups.
When using multiple program products simultaneously. If you are using more than program
product at the same time, ensure that your storage system is configured for optimal performance
(for example, sufficient cache). Contact HP Technical Support. Concurrent use affects the
performance and the operation of the other program products.
When using AIX host servers. Best performance results when P-VOLs are located on one AIX
host server and paired S-VOLs on another. The problem with using one AIX host server for
both P-VOLs and S-VOLs is that during the paircreate or pairresync operation, the P-VOL and
S-VOL have the same PVID. If the host server reboots when this is the case, it can mis-identify
the volumes and identify the S-VOL as the P-VOL after rebooting.
Preparing for resynchronization by Quick Restore. During a quick restore operation, in which
the contents of the P-VOL and S-VOL are swapped, the RAID levels, HDD types, and Cache
16 Requirements and planning
GID: Pair Volume Associated L1
LUN Type S-VOLs
0:00 L1 S-VOL NA
L2 P-VOL
0:01 L1 S-VOL NA
L2 P-VOL
NA NA NA
0:00 L2 S-VOL NA
0:01 L2 S-VOL NA
Associated L1 Associated
P-VOLs
L2 S-VOLs
1A-0:00 4A-0:00,
3B-0:01
1A-0:00 4B-0:00,
3B-0:01
NA NA
NA NA
NA NA
Associated L2
P-VOL
NA
NA
NA
1B-0:00
1B-0:00