When you enable the Bandwidth Throttler, Internet Information Server activates a set of Performance Monitor counters to monitor the behavior of the Bandwidth Throttler. You can identify these counters by the presence of the phrase "Async I/O" in the counter name. These counters are active only when the Bandwidth Throttler is enabled. If the Bandwidth Throttler is not enabled, the counters appear in Performance Monitor, but they always have a value of zero.
The bandwidth set in the Bandwidth Throttler applies to the combined bandwidth used by all three IIS services. As such, 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.
Table 7.7 Performance Monitor Counters for Monitoring the Bandwidth Throttler
Counter | Indicates |
Internet Information Services Global: Current Blocked Async I/O Requests | The number of requests blocked (that is, held in a buffer until the bandwidth clears) by the Bandwidth Throttler as reported during the most recent observation. |
Internet Information Services Global: Total Allowed Async I/O Requests | The number of requests allowed by the Bandwidth Throttler 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 the bandwidth clears) by the Bandwidth Throttler since the service was last started. |
Internet Information Services Global: Total Rejected Async I/O Requests | The number of requests rejected by the Bandwidth Throttler 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 the Bandwidth Throttler. |