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Finding Performance Bottlenecks
Part 1: Memory
More of this Feature
• Part 2: Disk Drives
• Part 3: Processor
• Part 4: Network
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"Performance or memory questions?"
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More of this Feature
• Part 1: Memory
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"Need help with Performance Monitor?"
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Related Resources
• Performance Monitor
• Chart CPU Usage
• Monitor Disk Usage
• Performance Resource Links
• System Utilities
From Other Guides
• Performance Tips
• Performance Tuning
• Performance Utilities
• Performance Tips
Elsewhere on the Web
• Monitor Disk Performance
• Monitoring a Remote Computer
In the previous feature, we introduced the Performance Monitor as an
excellent tool for measuring, charting, and logging system performance.
Although the Performance Monitor is interesting and even fun to use,
it can also be confusing and of little value if you don't know which
counters are significant and why. In this feature, we will begin looking
at several sets of counters that will help you determine if and where
your Windows 2000 system is experiencing bottlenecks.
One of the most common bottlenecks that Windows 2000/NT systems face
is memory. NT/2000 computers are notorious for being RAM hogs: the more
you can pack in a system, the better. However, there are counters that
you can measure that will show this quantitatively, and that can help
you build a case for adding more RAM.
There are two general areas to look to see if your system needs more
RAM: the paging file, and the various memory "pools." The
paging file is an actual file on your hard drive. When the operating
system runs out of physical RAM, it will temporarily move data out of
RAM to this file. Therefore, if monitoring this file shows heavy usage,
we know that the system is low on RAM, generally speaking. Here are
the counters to watch:
Paging File
Object: Memory
Counter: Pages /sec
Object: Logical Disk (location of the PAGEFILE.SYS)
Counter: Avg. Disk sec/Transfer
Note: In order to use the Logical Disk counters, you must turn them
on by typing "diskperf -yv" at a command prompt, and then
restarting the machine.
Interpretation: Multiplying these two counters will give you the percentage
of the disk access time being used by paging. If this is greater than
10% for a sustained period, you should add more RAM. If the Pages/Sec
value is consistently greater than 5, you should also consider adding
more RAM.
Memory Pools
Object: Server
Counter: Pool Nonpaged Failures
Interpretation: The number of times allocations from nonpaged pool have
failed. Failures indicate that the computer's physical memory is too
small.
Object: Server
Counter: Pool Paged Failures
Interpretation: Pool Paged Failures indicate that either physical memory
or a paging file is near capacity.
Object: Server
Counter: Pool Nonpaged Peak
Interpretation: This counter shows the maximum number of bytes of nonpaged
pool the server has had in use at any one point. This will indicate
how much physical memory the computer should have.
Although you can view these counters in a real-time chart window in
Performance Monitor, I recommend creating a log file and letting it
run during a typical twenty-four hour period, to get a more complete
picture of what's going on with your system.
From: http://windows.about.com/library/weekly/aa001112a.htm
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