Sun Java System Web Server 7.0 Update 4 Performance Tuning, Sizing, and Scaling Guide

ProcedureTo Control and Monitor the File Cache

  1. Add a NameTrans directive to the default object:

    NameTrans fn="assign-name" from="/nsfc" name="nsfc"

  2. Add an nsfc object definition:

    <Object name="nsfc">
    Service fn="service-nsfc-dump"

    This configuration enables the file cache control and monitoring function (nsfc-dump) to be accessed through the URI /nfsc. To use a different URI, change the from parameter in the NameTrans directive.

    The following is an example of the information you receive when you access the URI:

    Sun Java System File Cache Status (pid 3602)
    The file cache is enabled.
    Cache resource utilization
    Number of cached file entries = 174968 (152 bytes each, 26595136 total bytes)
    Heap space used for cache = 1882632616/1882632760 bytes
    Mapped memory used for medium file contents = 0/1 bytes
    Number of cache lookup hits = 47615653/48089040 ( 99.02 %)
    Number of hits/misses on cached file info = 23720344/324195
    Number of hits/misses on cached file content = 16247503/174985
    Number of outdated cache entries deleted = 0
    Number of cache entry replacements = 0
    Total number of cache entries deleted = 0
    Parameter settings
    ReplaceFiles: false
    ReplaceInterval: 1 milliseconds
    HitOrder: false
    CacheFileContent: true
    TransmitFile: false
    MaxAge: 3600 seconds
    MaxFiles: 600000 files
    SmallFileSizeLimit: 500000 bytes
    MediumFileSizeLimit: 1000001 bytes
    BufferSize: 8192 bytes
    CopyFiles: false
    Directory for temporary files: /tmp
    Hash table size: 1200007 buckets

    You can include a query string when you access the URI. The following values are recognized:

    • ?list: Lists the files in the cache.

    • ?refresh=n: Causes the client to reload the page every n seconds.

    • ?restart: Causes the cache to be shut down and then restarted.

    • ?start: Starts the cache.

    • ?stop: Shuts down the cache.

    If you choose the ?list option, the file listing includes the file name, a set of flags, the current number of references to the cache entry, the size of the file, and an internal file ID value. The flags are as follows:

    • C: File contents are cached.

    • D: Cache entry is marked for delete.

    • E: PR_GetFileInfo() returned an error for this file.

    • I: File information including size and modification date is cached.

    • M: File contents are mapped into virtual memory.

    • O: File descriptor is cached (when TransmitFile is set to true).

    • P: File has associated private data and appears on shtml files.

    • T: Cache entry has a temporary file.

    • W: Cache entry is locked for write access.