FCC cache parameters

The following table lists the values in the FMS_HOME/fcc.xml file available for FCC common cache parameters. See the FMS_HOME/fcc.xml.template file for all available elements. Name Default value Description FCC_CacheLocation $HOME\FCCCache|/tmp/FCCCache Defines the FCC root cache location. Each user's FCC cache is in a separate subdirectory below this location. The value to the left of | is used for Windows hosts. The value to the right of | is used for Linux hosts. The following table lists the values available for FCC whole file cache parameters. Name Default value Description FCC_CacheTableHashSize 1000 Deprecated. Defined the initial size of the internal FCC GUID lookup table. FCC_WholeFileCache Subdirectories 30 Defines the number of FCC whole file cache subdirectories. FCC_MaxWriteCacheSize 1G Defines the maximum size (in bytes) of the FCC whole file write cache. Use the suffixes K, M, G and T to represent kilobytes, megabytes, gigabytes, and terabytes, respectively. FCC_MaxReadCacheSize 1G Defines the maximum size (in bytes) of the FCC whole file read cache. Use the suffixes K, M, G and T to represent kilobytes, megabytes, gigabytes, and terabytes, respectively. FCC_MaximumRead CacheAge 180 Defines the maximum idle age (in days) of a file in the FCC whole file read cache. Files that have not been accessed in longer than the time period defined are removed from the cache. FCC_MinimumRead CacheAgeMinutes 240 Defines the minimum read cache age (in minutes). The FCC deletes files from its WholeFileReadCache only if they have not been accessed within the specified amount of time. The minimum value is one minute. Note Setting this parameter to a very high value makes the FCC whole file read cache purge ineffective. FCC_MaximumWrite CacheAge 180 Defines the maximum idle age (in days) of a file in the FCC whole file write cache. Files that have not been accessed in longer than the time period defined are removed from the cache. FCC_MinimumWrite CacheAgeMinutes 10 Defines the minimum write cache age (in minutes). The FCC deletes files from its WholeFileWriteCache only if they have not been accessed within the specified amount of time. The minimum value is one minute. Note Setting this parameter to a very high value makes the FCC whole file write cache purge ineffective. FCC_ReadCachePurgeSize Percentage 25 Defines the minimum percentage of free space purged when the FCC whole file read cache becomes full. For example, if set to 25, when the cache reaches 100% of its maximum size, the FCC begins to purge the least recently accessed files until the cache size is reduced to 75% or less of its maximum size. FCC_WriteCachePurgeSize Percentage 25 Defines the minimum percentage of free space purged when the FCC whole file write cache becomes full. For example, if set to 25, when the cache reaches 100% of its maximum size, the FCC begins to purge the least recently accessed files until the cache size is reduced to 75% or less of its maximum size. FCC_MinimumBackground IdleTimeSeconds 5 Allows prioritizing of background processing of whole file cache population requests. The FCC begins background processing of cache population requests only after it is free of foreground client data requests for the specified amount of time (in seconds). Once cache population begins, received foreground data requests do not interrupt a file download already in progress, they can introduce delays before the background cache population process progresses to the next file. Disable this behavior by setting this parameter to 0. Note Setting this parameter to a very high value makes the background cache file population functionality ineffective. FCC_MaxBackground Retries 3 Defines the maximum number of times a background whole file cache population request is retried due to a recoverable error. (Unrecoverable errors are not retried.) If the file is not successfully downloaded after the maximum number of retries, the request is discarded. Disable this behavior by setting this parameter to 0. The request is immediately discarded. Note Setting this parameter to a very high value can degrade FCC performance, requiring it to continually retry downloads that fail in a manner that is not obviously unrecoverable. The following table lists the values in the fcc.xml file available for FCC segment cache parameters. Name Default value Description FCC_MaximumNumberOf FilePages 40960 Defines the maximum number of header files. FCC_MaximumNumberOf Segments 512 Defines the number of data segments in the base segment file. This number does not include extents. FCC_HashBlockPages 2048 Defines the maximum number of hash block pages. Each hash block contains 128 hash entries. FCC_MaxExtentFiles 32 Defines the maximum number of extant files. FCC_MaxExtentFileSize Megabytes 16 Defines the maximum size (in megabytes) of each extent file. This number is rounded to a multiple of 16 megabytes. For example, a value of 258 results in 256 megabytes of segment data per extent file. The value of 256M represents 256 million megabytes, which is out of range.