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This soft copy for use by IBM employees only.
8.5.1.2 Using Performance Monitor
A good place to start measuring memory usage is the Performance Monitor.
Check the following object (Figure 115):
Object: Memory
Counter: Pages/sec.
This counter should be in the range of 5 or less. Anything above this level
indicates that your system is thrashing and could benefit from upgrading the
memory.
Note
Be careful. This value could be influenced by a poorly written application
that misbehaves. Carefully shut down all applications on your server when
you know you will not be impacting the users, until you are able to determine
which of your applications is causing the thrashing.
If you cannot find any application running on the server that is the cause of
the thrashing, you know that the server has insufficient resources and would
benefit from a memory upgrade. If you do find an application that does
cause the server to thrash, you will know which application to measure once
you have completed the memory upgrade.
Figure 115. Determining Memory Use
Pages/sec is the number of pages read from the disk or written to the disk to
resolve memory references to pages that were not in memory at the time of the
reference. This is the sum of Pages Input/sec and Pages Output/sec. This
counter includes paging traffic on behalf of the system cache to access file data
for applications. This value also includes the pages to/from uncached mapped
memory files. This is the primary counter to observe if you are concerned about
excessive memory pressure (that is, thrashing), and the excessive paging that
may result.
Use the Performance Monitor to check the following:
Object: Memory
Counter: Pages/sec
138 PC Server and Windows NT Integration Guide