540 DB2 Performance Expert for Multiplatforms V2.2
Operating system monitoring
In addition to a large variety of DB2 metrics, PE also keeps track and displays
OS-level metrics. There are two links in the PE System Overview window to view
Operating System Information links to the rather static data, such
as configured memory, installed CPUs, and file system information.
links to more volatile metrics about paging, processes, CPU
consumption, and disk utilization (Figure C-18). All OS-level data is enabled for
Figure C-18 Operating System monitoring
File system usage
As your BI system grows over time, you typically want to verify that the storage
resources are still sufficient. You might also want to keep an eye on storage that
is needed only temporarily. This is important because BI systems tend to perform
large sorts that might require some dedicated disk space. The OS Information
window provides an overview of storage resources (Figure C-19 on page 541).
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Figure C-19 File system usage
542 DB2 Performance Expert for Multiplatforms V2.2
Click the Disk Utilization (Delta) category of the OS Status window to display
disk I/O metrics (Figure C-20). This window shows the transferred (that is, read
and written) kilobytes and total number of I/O operations. Note that this data is
based on delta intervals. You can either manually refresh the window or see this
data based on the time between the recent two refreshes, or you can use the
Figure C-20 Disk I/O
CPU utilization, queues, and paging
The OS Status window also contains information about CPU and paging in the
Performance category (Figure C-21 on page 543).
The Run Queue Length field indicates how many processes are actually ready
for execution, and the Block Queue Length field shows the number of processes
that are waiting for I/O to finish.
Paging is counted in the number of pages being paged in or paged out.
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The CPU utilization is divided into user time, system time, I/O wait time, and idle
Both CPU utilization and paging data is based on delta values. You can either
click the Refresh button to see the data based on the time between previous and
current refresh, or you can use the auto-refresh feature.
The paging rate and block queue length data can also be visualized in the
System Health pane, and they can be used for threshold definitions for
Figure C-21 CPU utilization