One example method includes maintaining a deduplication data structure including one or more entries that each identify a respective fingerprint, and pointer, and also maintaining a ClientBlockList data structure comprising one or more entries that each identify a respective handle, retention date, and block, receiving a write request that identifies a handle, retention date, and block, computing a fingerprint of the block identified in the write request, determining, by the server, whether the fingerprint is in the deduplication data structure, and when the fingerprint is not in the deduplication data structure, storing the block identified in the write request at location ‘L’ in the deduplication data structure, and adding, to the deduplication data structure, an entry that identifies the fingerprint and the location ‘L,’ and adding, to the ClientBlockList data structure, an entry that identifies the handle, retention date, and fingerprint.