Methods, apparatuses and computer program products for processing and managing storage unit access

A method for processing a data access request in a second storage system, comprising:

• receiving a data access request redirected by a first storage system without being processed by a first storage unit in the first storage system via a redirection link from the first storage system to the second storage system, wherein the data access request is for a first storage unit in the first storage system, wherein the first storage unit is a secondary storage unit, wherein the first storage unit is a replication destination storage unit, and wherein the second storage unit is a replication source storage unit;
• the data access request being processed by a second storage unit in the second storage system associated with the first storage unit, the second storage unit being a primary storage unit;
• and
• after the data access request is redirected to the second storage unit in the second storage system via the redirection link and processed by the second storage unit, replicating the data access request back to the first storage unit in the first storage system via a replication link from the second storage system to the first storage system that is separate from the redirection link from the first storage system to the second storage system.

A method for managing a storage unit access, comprising:

• transmitting a data access request to a first storage unit in a first storage system, wherein the first storage unit is a secondary storage unit, and wherein the first storage unit is a replication destination storage unit, and wherein the data access request is redirected without being processed by the first storage unit to a second storage unit in a second storage system associated with the first storage unit via a redirection link from the first storage system to the second storage system, the second storage unit being a primary storage unit, and wherein the second storage unit is a replication source storage unit;
• after the data access request is redirected to the second storage unit in the second storage system via the redirection link and processed by the second storage unit, replicating the data access request back to the first storage unit in the first storage system via a replication link from the second storage system to the first storage system that is separate from the redirection link from the first storage system to the second storage system;
• and
• receiving an acknowledgment for the data access request from the first storage system.

An apparatus for processing a storage unit access in a first storage system, comprising:

• a processor;
• and
• a memory coupled to the processor, the memory having instructions stored therein, the instructions, when executed by the processor, causing the apparatus to:
• receive a data access request which is from a host system and for a first storage unit in the first storage system, wherein the first storage unit is a secondary storage unit, and wherein the first storage unit is a replication destination storage unit,
• the data access request being redirected without being processed by the first storage unit to a second storage unit in a second storage system associated with the first storage unit via a redirection link from the first storage system to the second storage system, wherein the second storage unit is a primary storage unit, and wherein the second storage unit is a replication source storage unit, and
• after the data access request is redirected to the second storage unit in the second storage system via the redirection link and processed by the second storage unit, the data access request being replicated back to the first storage unit in the first storage system via a replication link from the second storage system to the first storage system that is separate from the redirection link from the first storage system to the second storage system.

An apparatus for processing a storage unit access in a second storage system, comprising:

• a processor;
• and
• a memory coupled to the processor, the memory having instructions stored therein, the instructions, when executed by the processor, causing the apparatus to:
• receive a data access request redirected by a first storage system via a redirection link from the first storage system to the second storage system, the data access request having not been processed by the first storage unit, wherein the data access request is for a first storage unit in the first storage system, wherein the first storage unit is a secondary storage unit, wherein the first storage unit is a replication destination storage unit, and wherein the second storage unit is a replication source storage unit,
• the data access request being processed by a second storage unit in the second storage system associated with the first storage unit, the second storage unit being a primary storage unit, and
• after the data access request is redirected to the second storage unit in the second storage system via the redirection link and processed by the second storage unit, the data access request being replicated back to the first storage unit in the first storage system via a replication link from the second storage system to the first storage system that is separate from the redirection link from the first storage system to the second storage system.

An apparatus for managing a storage unit access, comprising:

• a processor;
• and
• a memory coupled to the processor, the memory having instructions stored therein, the instructions, when executed by the processor, causing the apparatus to:
• transmit a data access request to a first storage unit in a first storage system, wherein the first storage unit is a secondary storage unit, and wherein the first storage unit is a replication destination storage unit, and wherein the data access request is redirected without being processed by the first storage unit to a second storage unit in a second storage system associated with the first storage unit via a redirection link from the first storage system to the second storage system, the second storage unit being a primary storage unit, and wherein the second storage unit is a replication source storage unit,
• after the data access request is redirected to the second storage unit in the second storage system via the redirection link and processed by the second storage unit, the data access request being replicated back to the first storage unit in the first storage system via a replication link from the second storage system to the first storage system that is separate from the redirection link from the first storage system to the second storage system, and
• receive an acknowledgment for the data access request from the first storage system.

A computer program product having a non-transitory computer readable medium which stores a set of instructions to process a storage unit access in a first storage system;

• the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of:
• receiving a data access request which is from a host system and for a first storage unit in the first storage system, wherein the first storage unit is a secondary storage unit, and wherein the first storage unit is a replication destination storage unit;
• the data access request being redirected without being processed by the first storage unit to a second storage unit in a second storage system associated with the first storage unit via a redirection link from the first storage system to the second storage system, wherein the second storage unit is a primary storage unit, and wherein the second storage unit is a replication source storage unit;
• and
• after the data access request is redirected to the second storage unit in the second storage system via the redirection link and processed by the second storage unit, replicating the data access request back to the first storage unit in the first storage system via a replication link from the second storage system to the first storage system that is separate from the redirection link from the first storage system to the second storage system.

A computer program product having a non-transitory computer readable medium which stores a set of instructions to process a data access request in a second storage system;

• the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of:
• receiving a data access request redirected by a first storage system via a redirection link from the first storage system to the second storage system, the data access request having not been processed by the first storage unit, wherein the data access request is for a first storage unit in the first storage system, wherein the first storage unit is a secondary storage unit, wherein the first storage unit is a replication destination storage unit, and wherein the second storage unit is a replication source storage unit;
• the data access request being processed by a second storage unit in the second storage system associated with the first storage unit, the second storage unit being a primary storage unit;
• and
• after the data access request is redirected to the second storage unit in the second storage system via the redirection link and processed by the second storage unit, replicating the data access request back to the first storage unit in the first storage system via a replication link from the second storage system to the first storage system that is separate from the redirection link from the first sto qe system to the second storage system.

A computer program product having a non-transitory computer readable medium which stores a set of instructions to manage a storage unit access;

• the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of:
• transmitting a data access request to a first storage unit in a first storage system, wherein the first storage unit is a secondary storage unit, and wherein the first storage unit is a replication destination storage unit, and wherein the data access request is redirected without being processed by the first storage unit to a second storage unit in a second storage system associated with the first storage unit via a redirection link from the first storage system to the second storage system, the second storage unit being a primary storage unit, and wherein the second storage unit is a replication source storage unit;
• after the data access request is redirected to the second storage unit in the second storage system via the redirection link and processed by the second storage unit, redirecting the data access request back to the first storage unit in the first storage system via a replication link from the second storage system to the first storage system that is separate from the redirection link from the first storage system to the second storage system;
• and
• receiving an acknowledgment for the data access request from the first storage system.