Data accessing method and apparatus for performing the same using a host logical unit (HLUN)

摘要

The present invention discloses a data accessing method and an apparatus for performing the method. Through a newly-defined host logical unit (HLUN), a unique HLUN number is given to each LUN-to-LD/Partition mapping relationship, and the HLUN is present to external hosts. Therefore, all of the hosts in the same storage system may recognize different logical units (i.e., HLUN). Hence, when processing an Input/Output (IO) request issued from any one host, a storage virtualization controller (SVC) can correctly find the corresponding LD/Partition for accessing data without identifying the identity of the host.

主权项

1. A data accessing method for accessing data stored in a storage space, comprising:
an information-providing step performed by a controller for providing a host with a host-specific information in accordance with an identity (ID) of the host, thereby responding to at least one first command issued from the host; a basic-data-providing step performed by the controller for providing the host with basic data regarding a device type and properties of a target LUN, thereby responding to at least one second command issued from the host; a receiving step performed by the controller for receiving an Input/Output (IO) request issued from the host; an interpretation step performed by the controller for interpreting the IO request so as to obtain a logical unit number (LUN) carried by the IO request; a table lookup step performed by the controller for obtaining a logical drive/partition (LD/partition) associated with the LUN number by looking up in a host logical unit to LD/partition (HLUN-to-LD/Partition) mapping table without identifying the identity of the host, wherein in the HLUN-to-LD/Partition mapping table, a HLUN is uniquely corresponding to the accessible LD/partition; a data-accessing step performed by the controller for accessing data from the LD/partition; and a responding step performed by the controller for responding an execution result of the data-accessing step to the host; wherein, in response to the at least one second command, the controller further performs the steps of:
looking up in a host-ID table so as to obtain a host number corresponding to the identity of the host;determining if the host can recognize the target LUN;looking up in a LUN cross-reference information, or formula converting instead, and looking up in the HLUN-to-LD/Partition mapping table in accordance with the host number and the target LUN indicated by the second command, thereby obtaining an LD/partition associated with the target LUN; andreplying basic data and properties of the LD/partition to the host.