A method for generating a snapshot that records data transmitted to a storage system prior to a selected moment in time, while allowing a client server to continue sending data to the storage system, is disclosed. A snapshot marker is inserted into a cache, data continues to be flushed to disk until the snapshot marker is flushed from the cache, and a snapshot is performed. Additionally, a method for recording data stored in a storage system is disclosed that includes initiating a transaction with the storage system according to standard protocols, transmitting to the storage system a command representing a snapshot request, and performing a snapshot of the data. In accordance with one implementation, the command is transmitted as a SCSI command descriptor block.