Abstract: A redundant controller storage virtualization subsystem performing host-side IO rerouting and dynamic logical media unit reassignment. In one embodiment, when a host IO request is received by a storage virtualization controller that is not a logical media unit owner of the logical media unit addressed by the IO request, the IO can be rerouted to the alternate storage virtualization controller, the logical media unit owner, to be executed. In another embodiment, the assignment of logical media unit owner can be dynamically reassigned to the receiving storage virtualization controller which was originally not the logical media unit owner such that the receiving storage virtualization controller becomes new logical media unit owner to execute the IO request. In a further embodiment, the dynamic logical media unit reassignment can be performed according to the operating condition(s) of the storage virtualization system so as to improve the performance of the storage virtualization system.

Abstract: A method for remote asynchronous volume replication and apparatus therefore are disclosed. Asynchronous replication is applied to deal with data changes on the source volume on the local site incurred by Host IO requests. In coordination with the “point-in-time differential backup” technology, the data is subjected to be backuped to Source BAS on the local site (backup-on-write operation) only when the original data being written into the block of the source volume is different from the data of the corresponding block of the destination volume on the remote site. As a result, once a new data is written into the source volume completely, the host will be responded that its Host IO request is completed. Therefore, the data necessarily transmitted to the destination volume on the remote site can be minimized, and the problem of remote data transmission limited by network bandwidth can be prevented effectively, thereby keeping the operation performance of the storage system at a better level.

Abstract: A method for generating a virtual volume (VV) in a storage system architecture. The architecture comprises a host and one or more disk array subsystems. Each subsystem comprises a storage controller. One or more of the subsystems comprises a physical storage device (PSD) array. The method comprises the following steps: mapping the PSD array into a plurality of media extents (MEs), each of the MEs comprises a plurality of sections; providing a virtual pool (VP) to implement a section cross-referencing function, wherein a section index (SI) of each of the sections contained in the VP is defined by the VP to cross-reference VP sections to physical ME locations; providing a conversion method or procedure or function for mapping VP capacity into to a VV; and presenting the VV to the host. A storage subsystem and a storage system architecture performing the method are also provided.

Abstract: Method for accessing data in a storage system architecture, the architecture comprises at least one disk array subsystem, comprising the following steps. Provide a SAS for managing a first and a second media extent (ME) the at least one subsystem. Obtain a location index corresponding to a host LBA via a BAT. Obtain a location information of a physical section located in the first ME corresponding to the location index via a physical section to virtual section cross-referencing functionality. Update the cross-reference in the cross-referencing functionality so that the location information obtained from the cross-referencing functionality corresponding to the location index is the location information of the second physical section. A host IO request addressing the host LBA accesses data in the second physical section utilizing the location information of the second physical section.

Abstract: A method and apparatus for performing volume replication using a unified architecture are provided. Each volume has an exclusive volume log table (VLT) and an exclusive volume block update table (VBUT). The VLT is mainly used for recording the relationship between two volumes of a mirroring pair, and the VBUT is used for tracking the state of each data block of the volume itself. By means of the cross operations between the VLT and the VBUT, various volume replication processes such as volume copying and volume mirroring can be enabled under a unified architecture. Specifically, for each volume, different replication relationships with other volumes can be handled merely by administering its two exclusive tables. Hence, the method and apparatus provided by the present invention can advantageously simplify the architecture for synchronization replication and reduce the burdens of administrating tables, thereby making the operation of a storage system more efficient.

Abstract: A method for performing adaptive write caching in a storage virtualization subsystem is disclosed. In this method, criteria associated with an operation state of the storage virtualizalion subsystem for performing write caching are first defined. Then, the characteristics of a stream of at least one write input/output (IO) request sent out by a host entity are analyzed to make a determination of whether the stream meets the criteria. Thereafter, a new write IO request by the subsystem from the host entity is received, and write caching is performed to write data associated with the new write IO request to a physical storage device (PSD) array according to the determination.

Abstract: A method for media scan operations for storage system is disclosed. The method comprises the steps of arranging a range of sections of media of PSDs to perform media scan operations; scheduling the media scan operations; selecting a section in the range; verifying media of the selected section; determining the status of selected section; if the status is not ok, responding by proceeding with the corrective action processes, otherwise responding by selecting another section in the range to proceed with the verifying step, the determining step, and this responding step, until no more sections in the range to be verified. A storage subsystem implementing the method, a computer system comprising such storage subsystem, and a storage media having machine-executable codes stored therein for performing the method are also disclosed.

Abstract: A redundant external storage virtualization computer system. The redundant storage virtualization computer system includes a host entity for issuing an IO request, a redundant external storage virtualization controller pair coupled to the host entity for performing an IO operation in response to the IO request issued by the host entity, and a plurality of physical storage devices for providing storage to the computer system. Each of the physical storage devices is coupled to the redundant storage virtualization controller pair through a point-to-point serial signal interconnect. The redundant storage virtualization controller pair includes a first and a second storage virtualization controller both coupled to the host entity. In the redundant storage virtualization controller pair, when the second storage virtualization controller is not on line, the first storage virtualization controller will take over the functionality originally performed by the second storage virtualization controller.

Abstract: This specification discloses a method of managing data snapshot images in a storage system. The method includes the steps of: establishing a section allocation system that includes at least a media extent; establishing a section allocation table and a block association set in the media extent, wherein the section allocation table has a field containing information pointing to the block association set and the block association set corresponds to a Source Volume as the basis for performing a snapshot backup thereof; establishing a block association table in the block association set, wherein the block association table is used to store cross-reference information in order to correspond to backup data with the original storage addresses; and copying the data before updating the data into the section association set, when the data in the Source-Volume need to be updated.

Abstract: A method for dispatching of service requests in a redundant storage virtualization subsystem including a plurality of storage virtualization controllers is disclosed. The method comprises the steps of the host entity issuing a first service request to a first one of the SVCs; the first SVC handling the first service request, acquiring a first result of servicing the first service request, and returning the first result to the host entity the result; and, the host entity issuing a second service request to a second one of the SVCs; and, the second SVC handling the second service request, acquiring a second result of servicing the second service request, and returning the second result to the host entity the result. A storage virtualization subsystem implementing the method, a computer system comprising such storage virtualization subsystem, and a storage media having machine-executable codes stored therein for performing the method are also disclosed.

Abstract: A method for media scan operations for storage system is disclosed. The method comprises the steps of arranging a range of sections of media of PSDs to perform media scan operations; scheduling the media scan operations; selecting a section in the range; verifying media of the selected section; determining the status of selected section; if the status is not ok, responding by proceeding with the corrective action processes, otherwise responding by selecting another section in the range to proceed with the verifying step, the determining step, and this responding step, until no more sections in the range to be verified. A storage subsystem implementing the method, a computer system comprising such storage subsystem, and a storage media having machine-executable codes stored therein for performing the method are also disclosed.

Abstract: A redundant external storage virtualization computer system. The redundant storage virtualization computer system includes a host entity for issuing an IO request, a redundant external storage virtualization controller pair coupled to the host entity for performing an IO operation in response to the IO request issued by the host entity, and a plurality of physical storage devices for providing storage to the computer system. Each of the physical storage devices is coupled to the redundant storage virtualization controller pair through a point-to-point serial signal interconnect. The redundant storage virtualization controller pair includes a first and a second storage virtualization controller both coupled to the host entity.

Abstract: A redundant external storage virtualization computer system. The redundant storage virtualization computer system includes a host entity for issuing an IO request, a redundant external storage virtualization controller pair coupled to the host entity for performing an IO operation in response to the IO request issued by the host entity, and a plurality of physical storage devices for providing storage to the computer system. Each of the physical storage devices is coupled to the redundant storage virtualization controller pair through a point-to-point serial signal interconnect. The redundant storage virtualization controller pair includes a first and a second storage virtualization controller both coupled to the host entity. In the redundant storage virtualization controller pair, when the second storage virtualization controller is not on line, the first storage virtualization controller will take over the functionality originally performed by the second storage virtualization controller.