Monitoring and Tuning Your Server
Monitoring and Tuning Your Server |
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IIS 5.0 relies on the operating system to store and retrieve frequently-used Web pages and other files from the File System Cache. The File System Cache is particularly useful for servers of static Web pages, because Web pages tend to be used in repeated, predictable patterns.
Also, IIS 5.0 always reads sequentially. Sequential reading takes advantage of a Cache Manager feature called a read ahead. This occurs when the Cache Manager’s predictive algorithms detect sequential reading and begin to read larger blocks of data in each read operation. Read aheads can provide a significant performance boost to a process.
IIS 5.0 uses both the File System Cache and the IIS Object Cache, sometimes together. When a thread belonging to an IIS 5.0 service needs to open a file, the thread requests a file handle from the operating system. When it receives the handle, the thread uses the handle to open the file. Then, if space permits, the thread stores the handle in the IIS Object Cache and the system stores the file data in the File System Cache. Later, if that thread (or any other thread) needs the file, the file handle can be retrieved from the IIS Object Cache and the file contents can be retrieved from the File System Cache.