Performing copies in a storage system

A method for use in a storage system, wherein responsive to receiving a request to copy a first range of data from a first volume to a second range of a second volume, the method comprising:

• creating a third medium;
• storing an indication that a first medium underlies the third medium, wherein the first range of the first volume is associated with the first medium;
• associating the first volume with the third medium;
• creating a fourth medium;
• storing an indication that the first range of data in the first medium underlies the fourth medium;
• storing one or more indications that a second medium underlies all other data of the fourth medium, wherein the second volume is associated with the second medium;
• and
• associating the second volume with the fourth medium.

A non-transitory computer readable storage medium storing program instructions, wherein responsive to receiving a request to copy a first range of data from a first volume to a second range of a second volume, the program instructions are executable by a processor to:

• create a third medium;
• store an indication that the first medium underlies the third medium, wherein the first volume is associated with the first medium;
• associate the first volume with the third medium;
• create a fourth medium;
• store an indication that the first range of data in the first medium underlies the fourth medium;
• store one or more indications that the second medium underlies all other data of the fourth medium, wherein the second volume is associated with the second medium;
• and
• associate the second volume with the fourth medium.

A computer system comprising:

• one or more storage devices;
• and
• a storage controller coupled to the one or more storage devices;
• wherein in response to receiving a request to copy first data from a first location associated with a first existing medium in a first volume to a second location, the storage controller is configured to:
• create a first new medium;
• store a first indication that the first existing medium underlies the first new medium;
• and
• associate the first volume with the first new medium;
• if the second location is in the first volume, store a second indication that the first location in the first medium underlies the second location in the first new medium;
• if the second location is in a second volume associated with a second existing medium:
• create a second new medium;
• store a third indication the second existing medium underlies the second new medium;
• store a fourth indication that the first data underlies the second new medium;
• and
• associate the second volume with the second new medium.

A computer system comprising:

• one or more storage devices;
• and
• a storage controller coupled to the one or more storage devices;
• wherein in response to receiving a request to copy first data from a first location associated with a first existing medium in a first volume to a second location, the storage controller is configured to:
• create a first new medium;
• store a first indication that the first existing medium underlies the first new medium;
• and
• associate the first volume with the first new medium;
• and
• store a second indication that the first location in the first medium underlies the second location in the first new medium.