Efficient cloning of logical storage devices

A system comprising:

• a plurality of physical storage devices for storing data;
• a plurality of logical storage units, each logical storage unit including a plurality of data portions, each data portion corresponding to one or more physical locations within the plurality of physical storage devices;
• and
• memory having code stored thereon that, when executed, performs a method including:
• initiating an establishing of a target logical storage unit as a point-in-time image of a source logical storage unit using metadata associated with the source logical storage unit;
• initiating a defining of a state of a target mapping table to map data portions of the target logical storage unit to physical locations on the plurality of physical storage devices that are mapped to data portions of the source logical storage unit corresponding to the data portions of the target logical storage device;
• after initiating the defining, activating the target logical storage unit, including enabling access to the target logical storage unit by one or more host systems;
• receiving an I/O operation specifying a data portion of the target logical storage unit;
• determining, for a data portion of the source target storage unit corresponding to the specified data portion of the target logical storage unit, that that there is a pending write operation for the corresponding data portion that was pending before the activating of the target logical storage unit;
• combining data of the pending write operation with data specified by the received I/O operation;
• and
• storing the combined data at a first physical location on the plurality of physical storage devices allocated to the specified data portion of the target logical storage unit,
• wherein neither the data of the pending write operation nor the data specified by the received I/O operation are stored on one or more physical storage devices before the data of the pending write operation and the data specified by the received I/O operation are combined.

For a system including a plurality of physical storage devices for storing data and a plurality of logical storage units, each logical storage unit including a plurality of data portions, each data portion corresponding to one or more physical locations within the plurality of physical storage devices, one or more non-transitory computer-readable media having software stored thereon comprising software defining a method of establishing a target logical storage unit as a point-in-time image of a source logical storage unit, the software comprising:

• executable code that initiates an establishing of the target logical storage unit as the point-in-time image of the source logical storage unit using metadata associated with the source logical storage unit;
• executable code that initiates a defining of a state of a target mapping table to map data portions of the target logical storage unit to physical locations on the plurality of physical storage devices that are mapped to data portions of the source logical storage unit corresponding to the data portions of the target logical storage device;
• executable code that, after initiating the defining, activates the target logical storage unit, including enabling access to the target logical storage unit by one or more host systems;
• executable code that receives an I/O operation specifying a data portion of the target logical storage unit;
• executable code that determines, for a data portion of the source target storage unit corresponding to the specified data portion of the target logical storage unit, that that there is a pending write operation for the corresponding data portion that was pending before the activating of the target logical storage unit;
• executable code that combines data of the pending write operation with data specified by the received I/O operation;
• and
• executable code that stores the combined data at a first physical location on the plurality of physical storage devices allocated to the specified data portion of the target logical storage unit,
• wherein neither the data of the pending write operation nor the data specified by the received I/O operation are stored on one or more physical storage devices before the data of the pending write operation and the data specified by the received I/O operation are combined.