Q238145: How to Monitor Bandwidth Throttling
Article: Q238145
Product(s): Internet Information Server
Version(s): winnt:5.0
Operating System(s):
Keyword(s):
Last Modified: 04-FEB-2000
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The information in this article applies to:
- Microsoft Internet Information Services version 5.0
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SUMMARY
=======
When you enable bandwidth throttling, Internet Information Services (IIS)
activates a set of counters to monitor it in System Monitor (SysMon). These
counters can be identified by "Async I/O" in the counter name. These counters
are active only when bandwidth throttling is enabled. (If bandwidth throttling
is not enabled, the counters appear in SysMon, but they always have a value of
zero.)
MORE INFORMATION
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The Async I/O counters are part of the Internet Information Services Global
performance object. They represent totals for all of the IIS services. Bandwidth
is not measured for each service. The following table lists and describes the
Async I/O counters.
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| Counter | Indicates |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Internet Information Services Global: Current Blocked Async I/O Requests | The number of requests blocked (that is, held in a buffer until bandwidth is available) by bandwidth throttling as reported during the most recent observation. |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Internet Information Services Global: Total Allowed Async I/O Requests | The number of requests allowed by bandwidth throttling since the service was last started. |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Internet Information Services Global: Total Blocked Async I/O Requests | The number of requests blocked (that is, held in a buffer until bandwidth is available) by bandwidth throttling since the service was last started. |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Internet Information Services Global: Total Rejected Async I/O Requests | The number of requests rejected by bandwidth throttling since the service was last started. |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Internet Information Services Global: Measured Async I/O Bandwidth Usage/Minute | The number of bytes sent per minute as indicated by a sample taken by bandwidth throttling. |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
The bandwidth setting determines whether IIS accepts or rejects a request for a
static HTML page, based on periodic samples of the rate at which bytes are sent
on the server.
If the bandwidth used (as indicated by the sample) approaches the maximum set by
the user, bandwidth throttling blocks read requests, but allows write requests
and transmission requests. Read requests are blocked first, because they are
likely to result in further requests.
If the bandwidth used exceeds the maximum set by the user, bandwidth throttling
rejects read requests, blocks large write requests and transmission requests,
and allows small write requests and transmission requests.
To determine how many requests are being blocked and rejected, monitor the Async
I/O counters. These counters display cumulative totals, so it's best to use the
SysMon log to log the counter values. A spreadsheet can also be used to
calculate the rate over time. SysMon can be used to notify administrators when
the number of blocked or rejected requests exceeds a threshold.
Additional query words: iis
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Keywords :
Technology : kbiisSearch kbiis500
Version : winnt:5.0
Issue type : kbinfo
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