HP XP Array Manager Software - Manual (Page 18)

External Volume Usage Statistics
An external volume is a volume existing in an external storage system that is mapped to a volume in
the storage system using XP External Storage. Performance Monitor can monitor and display the usage
conditions for external volumes.
The information that can be monitored for an external volume differs from that of a typical volume.
For details on how to view usage conditions about external volumes, see “
Viewing Usage Statistics
about External Volumes in External Volume Groups ” on page 67.
Channel Processor Usage Statistics
A channel processor (CHP), which is contained in a channel adapter (CHA), processes host commands
and controls data transfer between hosts and the cache. A channel adapter contains multiple channel
processors that process host commands and control data transfer.
If monitoring data shows high overall CHP usage, you should consider installing additional CHAs. If
monitoring data shows that CHP usage is not balanced, you should consider moving some devices
that are defined on overloaded ports to ports with lower-usage CHPs to balance front-end usage.
For details on how to view usage statistics about channel adapters and channel processors groups,
see “
Viewing Usage Statistics about Channel Processors (CHPs) ” on page 69.
NOTE:
A channel adapter can also be called port controller.
Disk Processor Usage Statistics
A disk processor (DKP), which is contained in a disk adapter (DKA), controls data transfer between
the cache and the disk devices. A disk adapter contains multiple disk processors (DKPs).
If monitor data shows high DKP usage overall, you should consider installing additional HDDs and/or
DKAs, and then using XP Auto LUN to migrate the high-write-usage volumes (especially sequential
writes) to the new parity groups. If the monitor data shows that DKP usage is not balanced, you can
use XP Auto LUN to migrate volumes from high-usage parity groups to low-usage parity groups.
For more information on using XP Auto LUN, see the HP StorageWorks XP24000/XP20000 Auto
LUN Software User Guide.
When you consider migrating a volume from one parity group to another, take the following steps:
1. See Table 1 to determine the parity groups from which you want to migrate volumes.
The information in Table 1 does not apply to the XP20000 Disk Array because the XP20000
Disk Array has only one pair of DKA. If you are using an XP20000 Disk Array and you want to
know usage rates of DKPs, you must check the usage rate of each parity group. For details on
how to view usage statistics about disk adapters and disk processors, see “
Viewing Usage Stat-
istics about Disk Processors (DKPs) ” on page 70.
About Performance Monitor 18