Methods and systems for dynamic hashing in cache sub-systems are provided. The method includes analyzing a plurality of input/output (I/O) requests for determining a pattern indicating if the I/O requests are random or sequential; and using the pattern for dynamically changing a first input to a second input for computing a hash index value by a hashing function that is used to index into a hashing data structure to look up a cache block to cache an I/O request to read or write data, where for random I/O requests, a segment size is the first input to a hashing function to compute a first hash index value and for sequential I/O requests, a stripe size is used as the second input for computing a second hash index value.