The subject matter described herein is generally directed to detecting and managing collisions in storage. A hash identifier (ID) for a first block of data is calculated and a determination is made whether the calculated hash ID matches hash IDs associated with a storage. If the calculated hash ID matches at least one of the hash IDs, the first block of data is compared with a second block of data, associated with the hash IDs, in the storage. If the first block of data is different from the second block of data based on the comparison, a hash number is associated with the calculated hash ID and the first block of data is stored in storage using the calculated hash ID and associated hash number as an index to the first block of data in the storage. In this manner, collision between data blocks is detected and prevented.