Use the Cache attriubutes to create situations to monitor cache activity, such as the frequency of reads from cache pages, the percentage of cache copy requests that were successful, and the number of pages the cache has flushed to disk. Cache is a single-instance attribute group.
Async Copy Reads/sec The frequency of reads from cache pages that involve a memory copy of the data from the cache to the buffer for the application. The application regains control immediately even if the disk must be accessed to retrieve the page. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 34 for the pages read per second from the cache, enter 34.
Async Data Maps/sec The frequency that an application uses a file system, such as NTFS or HPFS, to map a page of a file into the cache to read the page, and does not wish to wait for the cache to retrieve the page if it is not in main memory. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 42 for the number of times an application uses a file system per second, enter 42.
Async Fast Reads/sec The frequency of reads from cache pages that bypass the installed file system and retrieve the data directly from the cache. Normally, file I/O requests invoke the appropriate file system to retrieve data from a file, but this path permits direct retrieval of cache data without file system involvement if the data is in the cache. Even if the data is not in the cache, one invocation of the file system is avoided. If the data is not in the cache, the request (application program call) gets control immediately. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 26 for the number of times cache pages bypass the installed system, enter 26.
Async MDL Reads/sec The frequency of reads from cache pages using a Memory Descriptor List (MDL) to access the pages. The MDL contains the physical address of each page in the transfer, thus permitting Direct Memory Access (DMA) of the pages. If the accessed page(s) are not in main memory, the calling application program does not wait for the pages to fault in from disk. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 42 for the number of times cache pages are read using an MDL to access the pages, enter 42.
Async Pin Reads/sec The frequency of reading data into the cache prior to writing the data back to disk. Pages read in this fashion are pinned in memory at the completion of the read. The file system regains control immediately even if the disk must be accessed to retrieve the page. While pinned, the physical physical address for the page is not altered. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 33 for the number of times per second data is read into the cache prior to writing the data back to disk, enter 33.
Copy Read Hits % The percentage of cache copy read requests that hit the cache, that is, that did not require a disk read to provide access to the page in the cache. A copy read is a file read operation that is satisfied by a memory copy from a cache page to the buffer for the application. The LAN Redirector uses this method to retrieve cache information, as does the LAN Server for small transfers. This is a method used by the disk file systems as well. Valid format is a numeric string in the range 0 to 100 (expressing a percentage). For example, to express 17 percent of cache copy read requests that hit the cache, enter 17.
Copy Reads/sec The frequency of reads from cache pages that involve a memory copy of the data from the cache to the buffer for the application. The LAN Redirector uses this method to retrieve cache information, as does the LAN Server for small transfers. This is a method used by the disk file systems as well. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 42 for the number of times cache pages are read using a memory copy of the data from the cache to the buffer for the application, enter 42.
Data Flush Pages/sec The number of pages the cache has flushed to disk as a result of a request to flush or to satisfy a write-through file write request. More than one page can be transferred on each flush operation. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 125 for the number of pages the cache has flushed to disk, enter 125.
Data Flushes/sec The frequency with which the cache has flushed its contents to disk as the result of a request to flush or to satisfy a write-through file write request. More than one page can be transferred on each flush operation. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 43 for the number of times the cache has flushed its contents to disk, enter 43.
Data Map Hits % The percentage of data maps in the cache that could be resolved without having to retrieve a page from the disk, that is, the page was already in physical memory. Valid format is a numeric string in the range 0 to 100 (expressing a percentage). For example, to express 12 percent of data maps in the cache that could be resolved without retrieving a page from the disk, enter 12.
Data Map Pins/sec The frequency of data maps in the cache that resulted in pinning a page in main memory, an action usually preparatory to writing to the file on disk. While pinned, the physical address for a page in main memory and the virtual address in the cache is not altered. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 34 for the number of times a page was pinned to main memory, enter 34.
Data Maps/sec The number of times per second that a file system, such as NTFS or HPFS, maps a page of a file into the cache to read the page. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 46 for the number of times a file system maps a page into the cache to read it, enter 46.
Fast Read Not Possibles/sec The frequency of attempts by an Application Program Interface (API) function call to bypass the file system to get at cache data that could not be honored without invoking the file system. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 126 for the number of attempts by an API call to bypass the file system to get at cache data, enter 126.
Fast Read Resource Misses/sec The frequency of cache misses necessitated by the lack of available resources to satisfy the request. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 55 for the number of cache misses due to lack of resources, enter 55.
Fast Reads/sec The frequency of reads from cache pages that bypass the installed file system and retrieve the data directly from the cache. Normally, file I/O requests invoke the appropriate file system to retrieve data from a file, but this path permits direct retrieval of cache data without file system involvement if the data is in the cache. Even if the data is not in the cache, one invocation of the file system is avoided. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 32 for the number of times reads from cache pages bypass the installed system, enter 55.
Lazy Write Flushes/sec The frequency with which the Lazy Write thread flushes its contents to disk. Lazy Writing is the process of updating the disk after the page has been changed in memory, so the application making the change to the file does not have to wait for the disk write to complete before proceeding. More than one page can be transferred on each write operation. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 67 for the number of times the Lazy Write thread writes to disk, enter 67.
Lazy Write Pages/sec The frequency with which the Lazy Write thread for the cache writes to disk. Lazy Writing is the process of updating the disk after the page has been changed in memory, so the application making the change to the file does not have to wait for the disk write to complete before proceeding. More than one page can be transferred on a single disk write operation. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 124 for the number of times the Lazy Write thread writes to disk, enter 124.
MDL Read Hits % The percentage of cache Memory Descriptor List (MDL) read requests that hit the cache, that is, that did not require disk accesses to provide memory access to the page(s) in the cache. Valid format is a numeric string in the range 0 to 100 (expressing a percentage). For example, to express 15 percent of MDL read requests that hit the cache, enter 15.
MDL Reads/sec The frequency of reads from cache pages that use a Memory Descriptor List (MDL) to access the data. The MDL contains the physical address of each page involved in the transfer, and thus can employ a hardware Direct Memory Access (DMA) device to effect the copy. The LAN Server uses this method for large transfers out of the server. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 55 for the number of reads from cache pages that use an MDL to access the data, enter 55.
Pin Read Hits % The percentage of cache pin read requests that hit the cache, that is, that did not require a disk read to provide access to the page in the cache. While pinned, the physical address for the page in the cache is not altered. The LAN Redirector uses this method for retrieving cache information, as does the LAN Server for small transfers. This is usually the method used by the disk file systems as well. Valid format is a numeric string in the range 0 to 100 (expressing a percentage). For example, to express 23 percent of cache pin read requests that hit the cache, enter 23.
Pin Reads/sec The frequency of reading data into the cache preparatory to writing the data back to disk. Pages read in this fashion are pinned in memory at the completion of the read. While pinned, the physical address for a page in the cache is not altered. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 89 for the number of reads into the cache pages prior to writing the data back to disk, enter 89.
Read Aheads/sec The frequency of cache reads where the cache detects sequential access to a file. The read aheads permit the data to be transferred in larger blocks than those being requested by the application, reducing the overhead per access. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 45 for the number of reads into the cache where the cache detects sequential access to a file, enter 45.
Sync Copy Reads/sec The frequency of reads from cache pages that involve a memory copy of the data from the cache to the buffer for the application. The file system does not regain control until the copy operation is complete, even if the disk must be accessed to retrieve the page. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 128 for the number of reads that involve a memory copy of the data from the cache to the buffer, enter 128.
Sync Data Maps/sec The frequency with which a file system, such as NTFS or HPFS, maps a page of a file into the cache to read the page, and wishes to wait for the cache to retrieve the page if it is not in main memory. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 35 for the number of times a file system maps a page of a file into the cache to read the page, enter 35.
Sync Fast Reads/sec The frequency of reads from cache pages that bypass the installed file system and retrieve the data directly from the cache. Normally, file I/O requests invoke the appropriate file system to retrieve data from a file, but this path permits direct retrieval of cache data without file system involvement if the data is in the cache. Even if the data is not in the cache, one invocation of the file system is avoided. If the data is not in the cache, the request (application program call) waits until the data is retrieved from disk. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 55 for the number of reads from cache pages that bypass the installed file system, enter 55.
Sync MDL Reads/sec The frequency of reads from cache pages that use a Memory Descriptor List (MDL) to access the pages. The MDL contains the physical address of each page in the transfer, thus permitting Direct Memory Access (DMA) of the pages. If the accessed page(s) are not in main memory, the caller waits for the pages to fault in from the disk. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 63 for the number of reads from cache pages that use an MDL to access the pages, enter 63.
Sync Pin Reads/sec The frequency of reading data into the cache preparatory to writing the data back to disk. Pages read in this fashion are pinned in memory at the completion of the read. The file system does not regain control until the page is pinned in the cache, in particular if the disk must be accessed to retrieve the page. While pinned, the physical address for a page in the cache is not altered. Valid values are positive integers in the range 0 to 2147483647 and can include the use of the *AVG, *MIN, *MAX, or *SUM functions. For example, to express 127 for the number of reads into the cache prior to writing the data back to disk, enter 127.
System Name The network name of the source of this information. Valid format is a text string of up to 64 characters.
Timestamp The date and time the Tivoli Enterprise Monitoring Server samples the data. Standard 16-character date/time format (CYYMMDDHHMMSSmmm), where:
C |
Century (0 for 20th, 1 for 21st) |
YY |
Year |
MM |
Month |
DD |
Day |
HH |
Hour |
MM |
Minute |
SS |
Second |
mmm |
Millisecond |
Use simple text strings as described above. For example, enter 0971009130500000 to express October 9, 1997, 1:05:00 pm.