The number of kilobyte blocks allocated to the cache is defined in the third field of the CacheInfo file. You can use the -blocks option to override the number of cache blocks; the unit of measure associated with the cache block size is always kilobytes. The Cache Manager heuristically divides the number of blocks by 8 to determine the number of cache chunks in a disk cache. The following example sets the number of disk blocks allocated for the cache to 75,000 kilobyte blocks:
dfsd -blocks 75000
The default number of cache chunks in a disk cache is computed as the number of cache blocks divided by 8; you can use the -files option with a positive integer not greater than 32,000 to override this default. To use your cache most effectively, issue the du command on the cache directory to determine the number of cache blocks used; compare this number to the number of blocks allocated to the cache. If you are not using 90% of the cache, increase the number of chunks (V files). The following example sets the number of chunks to 2000:
dfsd -files 2000
The default chunk size for a disk cache is 64 kilobytes (2-to-the-16th-power); the unit of measure associated with the chunk size is always bytes. You can use the -chunksize option to override the default chunk size. Provide an integer between 13 and 18 to be used as an exponent of 2. For example, a value of 15 sets the chunk size to 32 kilobytes (2-to-the-15th-power = 32,768); a value of 16 equals the default for disk caches (2-to-the-16th-power = 64 kilobytes). A value less than 13 or greater than 18 returns the chunk size to the default (as does a value of 16). The following example sets the chunk size to 16 kilobytes (2-to-the-14th-power):
dfsd -chunksize 14
For a disk cache, the default number of dcache entries duplicated in memory is 100. You can use the -dcache option with a positive integer to change the default. It is usually not necessary to duplicate more than 100 entries in memory. However, because memory access is faster than disk access, increasing the number of dcache entries stored in memory may improve performance slightly. The following example sets the number to 250:
dfsd -dcache 250
When altering a disk cache configuration, any combination of dfsd options is allowed. However, the cache size defined in the CacheInfo file or with the -blocks option cannot be exceeded with the -files or -chunksize option.