Cache performance counters
The following table lists the performance counters for the Microsoft Forefront Threat Management Gateway cache.
| Performance counter | Description |
|---|---|
Disk Bytes Retrieve Rate (KB/sec) |
Measures the rate at which bytes of data are retrieved from the disk cache. This counter is similar to the Disk URL Retrieve Rate counter but monitors bytes rather than URLs. |
Disk Cache Allocated Space (KB) |
Measures how much space is being used by the disk cache. It will be equal to or less than the amount configured for the disk cache. |
Disk Content Write Rate (Writes/sec) |
Measures the number of writes per second to the disk cache for the purpose of writing URL content to the cache disk. |
Disk Failure Rate (Failures/sec) |
Measures the number of input/output (I/O) failures per second. An I/O failure occurs when Forefront TMG fails to read from or write to the disk cache. This counter, with the Total Disk Failures counter, clearly indicates disk cache problems. |
Disk URL Retrieve Rate (URL/sec) |
Measures how many URLs are sent to clients from the disk cache in one second. This is a useful counter to measure at peak and off-peak times in order to check how the disk cache is performing. It can be compared with the Memory URL Retrieve Rate counter to determine how cache disk and memory are being utilized. |
Max URLs Cached |
Measures the maximum number of URLs that have been stored in the cache. |
Memory Bytes Retrieved Rate (KB/sec) |
Measures the rate at which bytes of data are retrieved from the memory cache. This counter is similar to the Memory URL Retrieve Rate counter but monitors bytes rather than URLs. |
Memory Cache Allocated Space (KB) |
Measures how much space is being used by the memory cache. It should be equal to or less than the amount configured for the memory cache. |
Memory URL Retrieve Rate (URL/sec) |
Measures how many URLs are sent to clients from the memory cache in one second. This is a useful counter to measure at peak and off-peak times in order to check how the memory cache is performing and whether available memory allocated for caching purposes is being used efficiently. |
Memory Usage Ratio Percent (%) |
Shows the percentage of the total amount of cache fetches that are from the memory cache. A high percentage may indicate that it is worthwhile to allocate more available memory resources to the cache. A low percentage may indicate that memory resources may be better used elsewhere. |
Total Disk Bytes Retrieved (KB) |
Measures the cumulative number of disk bytes that have been retrieved from the disk cache. This counter, added to the Total Memory Bytes Retrieved counter, indicates the total number of bytes retrieved from the cache. |
Total Disk Failures |
Measures the number of times that the Web proxy failed to read from or write to the disk cache due to an I/O failure. A low counter indicates that a disk is performing properly. A high counter indicates that a cache disk is too small, too slow, or corrupted. |
Total Disk URLs Retrieved |
Measures the cumulative number of URLs that have been retrieved from the disk cache. This counter, added to the Total Memory URLs Retrieved counter, indicates the total number of URLs retrieved from the cache. |
Total Memory Bytes Retrieved (KB) |
Measures the cumulative number of memory bytes that have been retrieved from the memory cache in response to client requests to the cache. A low number might indicate that memory resources dedicated to the cache are not being used efficiently. A high number might indicate that more memory resources should be allocated to the cache. |
Total Memory URLs Retrieved |
Measures the cumulative number of URLs that have been retrieved from the memory cache in response to client requests to the cache. A low number might indicate that memory resources dedicated to the cache are not being used efficiently. A high number might indicate that more memory resources should be allocated to the cache. |
Total URLs Cached |
Measures the cumulative number of URLs that have been stored in the cache. If this counter and the URLs in the cache counter are low, it may indicate a problem with the cache. The cache may not be configured for optimal use, or the cache size may be too small. |
URL Commit Rate (URL/sec) |
Indicates the speed at which URLs are being written to the cache. If the rate of this counter is comparable to the rate of the Disk Failure Rate counter, it indicates that a high proportion of attempts to write to the cache are failing. This could indicate a problem with cache configuration, a cache disk that is too slow, or a cache size that is too small. |
URLs in Cache |
Measures the current number of URLs in the cache. |
Cache Hit Percentage for Range Requests |
Shows the percentage of bytes served from the cache for responses to HTTP requests containing range headers. |
Bytes actually requested from server for range requests/Bytes in range requests |
Shows as a percentage the bytes that were requested from the server for range requests divided by the number of bytes in range requests (when the cache rule enabled range request caching). |