Flexible LUN/LBA interface for content addressable reference storage

A first LUN/LBA processing tier in a content addressed storage (CAS) system performing actions comprising:

• a. receiving an input/output (I/O) operation request, associated application-level LUN/LBA combination, and optionally, content data from an application program,
• b. passing said content data to a second OID processing tier if content data is received from said application program,
• c. using said application-level LUN/LBA combination received from said application program or using an OID returned from second OID processing tier if said content data was passed to said second OID processing tier in previous step to determine whether corresponding or same OID exists in a high-level OID table,
• d. determining whether a write, over-write, or an addition operation is allowed or if an operation is denied, based on said step of determining whether corresponding or same OID exists in said high-level OID table and said access property,
• e. passing said operation information and either:
• an OID if a retrieval operation is requested or an LUN/LBA address combination element location and associated content data for any other operation, and
• f. updating said high-level OID table with a new OID for an associated application-level LUN/LBA if a write, over-write, or an addition operation is allowed.

A second Object ID (OID) processing tier in a content addressed storage (CAS) system performing actions comprising:

• a. receiving an application-level LUN/LBA address combination and optionally, content data from either an application program or a first LUN/LBA processing tier,
• b. receiving a received OID from said first LUN/LBA processing tier if said content data is not received,
• c. hashing said content data to generate a generated OID if said content data is received,
• d. determining a physical LUN/LBA by using said received OID to consult a low-level OID table,
• e. determining whether a generated OID exists in a high-level OID table by comparing said generated OID to stored OIDs stored in said high-level OID table,
• f. updating said high-level OID table with said generated OID if said generated OID does not exist in said high-level OID table,
• g. passing a write request, said content data, and a location of OID in said low-level OID table to a third storage subsystem LUN/LBA processing tier if said content data is received in step a, based on step d and operations allowed by an access property,
• h. updating said low-level OID table with said generated OID and incrementing a counter associated with said generated OID, if said write request and said content data are passed to said third storage subsystem LUN/LBA processing tier,
• i. passing a retrieval request and a physical LUN/LBA combination to said third storage subsystem LUN/LBA processing tier if said received OID was received in step b, based on step e and operations allowed by said access property,
• j. passing to said third LUN/LBA processing tier said received OID if said write request and said content data are passed to said third storage subsystem LUN/LBA processing tier, and
• k. receiving said content data from said third storage subsystem LUN/LBA processing tier, if said retrieval request and said physical LUN/LBA are passed to said third storage subsystem LUN/LBA processing tier.

An third storage subsystem LUN/LBA processing tier in a content addressed storage (CAS) system performing actions comprising:

• a. receiving from a second OID processing tier a write request or a retrieval request and associated data,
• b. using an OID received from said second OID processing tier to determine associated LUN/LBA combination,
• c. writing to an LUN/LBA combination if a write request and associated content data is received,
• d. retrieving from an LUN/LBA if a retrieval request and an associated OID is received,
• e. re-hashing content data retrieved from an LUN/LBA combination if a retrieval request and an associated OID is received,
• f. comparing results of re-hashing step with an OID associated with said LUN/LBA combination stored in a low-level OID table, and
• g. passing to said second OID processing tier content data if a retrieval request and an associated OID was received.

A system for Content Addressed Storage (CAS) having a Logical Unit Number/Logical Block Address (LUN/LBA) interface comprising:

• a. a first LUN/LBA processing tier configured to receive at least a high-level LUN/LBA combination and optionally content data from an application,
• b. a second OID processing tier configured to provide an OID, either by generating said OID from said content data optionally received by said first LUN/LBA processing tier, or by receiving said OID from said application,
• c. a storage subsystem LUN/LBA processing tier configured to receive said OID provided by said second OID processing tier and to access a low-level LUN/LBA combination,
• d. a first table providing a correspondence between said high-level LUN/LBA combination and said OID, and
• e. a second table providing a correspondence between said low-level LUN/LBA combination and said OID.