HTTP.sys Cache Counters (IIS 6.0)
Table 7.5 describes the preferred or ideal values for HTTP.sys response cache counters. For more information about IIS 6.0 counters, see the Performance Counters Reference.
| Table 7.5 Preferred Values for HTTP.sys Response Cache Counters | |
| Object\Counter | Preferred or Ideal Value |
Web Service Cache\Kernel: Current URIs Cached | The value of this counter should nearly equal the total number of cacheable responses on the server (presuming that all cacheable responses have been cached). If this value is considerably lower than the total number of cacheable responses on the server, make sure the corresponding files are not larger than the default size, 256 KB. For information about the criteria that determine which files cannot be cached in the HTTP.sys response cache, see Events and Conditions That Disable HTTP.sys Response Caching. |
Web Service Cache\Kernel: Total Flushed URIs | As low as possible. The value of this counter represents the number of times a response was flushed. Note that responses are flushed from the cache if the associated file is edited or changed in any way, or if the file is not requested within 120 seconds. |
Web Service Cache\Kernel: Total URIs Cached | Depends on content, but the value of this counter should nearly equal the total number of cacheable responses on the server (presuming all cacheable responses have been cached). If this value is significantly larger than the total number of cacheable responses on the server, the HTTP.sys response cache is caching responses, flushing responses, and then caching responses again, which can impact performance and scalability. Investigate why responses are being flushed from the cache. If the value of this counter is significantly lower than the total number of cacheable responses on your sites, determine why some of the corresponding content files are not being cached. |
Web Service Cache\Kernel: URI Cache Flushes | As low as possible. This counter denotes the number of times the flush algorithm has been called. Note that a response will be flushed from the cache if the corresponding file is edited or changed in any way, or if the file was not requested within 120 seconds. |
Web Service Cache\Kernel: Cache Hits | As high as possible. This counter is incremented continually. If the value of this counter is very low, investigate why requests are not finding the cached response. |
Web Service Cache\Kernel: Cache Hits % | Depends on content. The value of this counter should reflect the ratio of requests for cacheable content to requests for content that is not cacheable. If, for example, roughly half the requests to your sites are for cacheable content, the value of this counter should be close to 50 percent. |
Web Service Cache\Kernel: URI Cache Hits/sec | As high as possible. |
Web Service Cache\Kernel: URI Cache Misses | Depends on content. All requests for content that cannot be cached result in a cache miss. If the value of this counter is high and the value of Cache Hits is low, investigate why your responses are not being cached. |
