Abstract: A snapshot lookup table (SLT) and snapshot pointer structure(s) (SPSs) may be provided for a logical data unit (LSU), each SPS entry corresponding to an LSU data portion and a physical storage location at which data is stored for the data portion for a particular snapshot. A current lookup table (CLT) for a current time may be provided for an LSU, including an entry for each LSU data that points to a respective entry of an SPS. Each time a first write following the creation of a snapshot is made to an LSU data portion, the corresponding CLT entry may be updated to point to the SPS entry that was updated to point to an LSU track table entry. To create a snapshot, a snapshot lookup table (SLT) is created for each snapshot, and the contents of the CLT are copied to the newly created SLT.

Abstract: A snapshot lookup table (SLT) and snapshot pointer structure(s) (SPSs) may be provided for a logical data unit (LSU), each SPS entry corresponding to an LSU data portion and a physical storage location at which data is stored for the data portion for a particular snapshot. A current lookup table (CLT) for a current time may be provided for an LSU, including an entry for each LSU data that points to a respective entry of an SPS. Each time a first write following the creation of a snapshot is made to an LSU data portion, the corresponding CLT entry may be updated to point to the SPS entry that was updated to point to an LSU track table entry. To create a snapshot, a snapshot lookup table (SLT) is created for each snapshot, and the contents of the CLT are copied to the newly created SLT.

Abstract: Replication of a storage object to a remote storage array is seamlessly maintained by i) while write operations directed to the storage object are being collected into a set of write cycles that are stored in a master storage array, also collecting the write operations directed to the storage volume into a set of write cycles stored in a slave storage array, and ii) in response to detecting a failure of the master storage array, and while the host computer continues to access the storage object using a copy of the storage object located in the slave storage array, transmitting the write cycles stored in the slave storage array to the remote storage array, so that the remote storage array can apply the write operations in the write cycles it receives from the slave storage array on the copy of the storage object contained in the remote storage array.