Dynamically controlling a file system write cache

An apparatus, comprising:

• a storage device;
• a memory configured to store a file system write cache;
• and
• a processor configured:
• to execute a block manager configured to manage multiple storage regions on the storage device;
• and
• to execute a file system manager configured:
• to initialize the file system write cache to have a default cache size, the default cache size corresponding to a first storage capacity of a default number of the storage regions;
• to determine a current number of the storage regions that are not in use by the block manager;
• upon detecting that the current number is less than the default number, to resize the file system write cache to a reduced cache size that corresponds to a second storage capacity of the current number of the storage regions;
• and
• to determine, while the file system write cache has the reduced cache size, a subsequent number of the storage regions that are not in use by the file system, and upon detecting that the subsequent number is greater than the current number, to resize the file system write cache to an expanded cache size that corresponds to a third storage capacity comprising a lesser of the subsequent number of the storage regions and the first storage capacity.

A computer program product, the computer program product comprising:

• a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising:
• computer readable program code configured to initialize, by a processor executing a file system in communication with a block manager managing multiple storage regions on a storage device, a file system write cache to have a default cache size, the default cache size corresponding to a first storage capacity of a default number of the storage regions;
• computer readable program code configured to determine a current number of the storage regions that are not in use by the block manager;
• computer readable program code configured upon detecting that the current number is less than the default number, to resize the file system write cache to a reduced cache size that corresponds to a second storage capacity of the current number of the storage regions;
• and
• computer readable program code configured to determine, while the file system write cache has the reduced cache size, a subsequent number of the storage regions that are not in use by the file system, and upon detecting that the subsequent number is greater than the current number, to resize the file system write cache to an expanded cache size that corresponds to a third storage capacity comprising a lesser of the subsequent number of the storage regions and the first storage capacity.