Patent ID: 8862642

Claim:
A method for caching data in a distributed file system over a network, comprising: receiving data at a node device for writing to a parent file that is maintained on a stable storage device; caching the received data prior to writing the received data to the parent file by both storing the received data in a node cache and storing the received data in a logstore, wherein the logstore is separately maintained on the stable storage device and the node cache is separately maintained on an unstable storage device on the node device; employing a data block associated with the logstore to include a bit map that identifies valid and invalid data blocks in the logstore, wherein each sub-block in the bit map corresponds to a different data block in the logstore; periodically writing all data in the node cache to the parent file on the stable storage device, wherein the written data is purged from the node cache; and invalidating the data blocks of all data in the logstore that correspond to the data written to the parent file on the stable storage device by deallocating each corresponding sub-block in the bit map.