Patent ID: 6895415

Claim:
A computer-implemented method for managing data snapshots among at least first and second storage volumes, comprising: invoking a snapshot relationship between the volumes; in response to the invoking act, establishing a logical copy of data from the first storage volume on the second storage volume; establishing respective first and second snapshot tables for the volumes, each table including a source volume column and a target volume column; in response to a read request for one or more read chunks in a “read” one of the volumes, accessing the snapshot table associated with the “read” volume, either one of the first and second storage volumes being selectable as the read volume; directing the read to the source volume as indicated for the read chunks in the source column of the snapshot table associated with the “read” volume; in response to a write request for one or more write chunks in a “write” one of the volumes, accessing the table associated with the “write” volume, either one of the first and second storage volumes being selectable as the write volume; and directing the write to the target volume as indicated for the write chunks in the target column of the table associated with the “write” volume.