Abstract: A method and apparatus for booting a clustered management system is provided where the configuration information required to boot the system is stored within the system itself. The techniques cope with several issues including finding the configuration data on the physical disk before the logical disk system is established, coping with replicated copies of configuration data, network partitions and disk drive failures that may prevent a booting node to have perfect knowledge of the state of the entire system, and active nodes modifying or moving configuration data while the booting node is searching for a consistent, correct copy of configuration data.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: Techniques are provided for assigning read requests to storage devices in a manner that reduces the likelihood that any storage device will become overloaded or underutilized. Specifically, a read-request handler assigns read requests that are directed to each particular item among the storage devices that have copies of the item based on how busy each of those storage devices is. Consequently, even though certain storage devices may have copies of the same item, there may be times during which one storage device is assigned a disproportionate number of the reads of the item because the other storage device is busy with read requests for other items, and there may be other times during which other storage device is assigned a disproportionate number of the reads of the item because the one storage device is busy with read request for other items.

Abstract: Techniques are described for logically isolating data I/O requests from different operating systems (OSes) for a same multi-tenant storage system (MTSS). Techniques provide for OSes and the MTSS to obtain security tokens associated with the OSes. In an embodiment, an OS uses a security token to generate an authentication token based on the contents of a data input/output (I/O) request and sends the authentication token to the MTSS along with the data I/O request. When an MTSS receives such data I/O request, MTSS retrieves its own copy of the security token associated with the OS and generates its own authentication token based on the contents of the received data I/O request. If the authentication token generated by the MTSS matches the authentication token generated by the OS, then the data I/O request is successfully authenticated. Otherwise, if the authorization tokens fail to match, then the data I/O request has been compromised.

Abstract: Techniques are described for logically isolating data I/O requests from different operating systems (OSes) for a same multi-tenant storage system (MTSS). Techniques provide for OSes and the MTSS to obtain security tokens associated with the OSes. In an embodiment, an OS uses a security token to generate an authentication token based on the contents of a data input/output (I/O) request and sends the authentication token to the MTSS along with the data I/O request. When an MTSS receives such data I/O request, MTSS retrieves its own copy of the security token associated with the OS and generates its own authentication token based on the contents of the received data I/O request. If the authentication token generated by the MTSS matches the authentication token generated by the OS, then the data I/O request is successfully authenticated. Otherwise, if the authorization tokens fail to match, then the data I/O request has been compromised.

Abstract: A method and apparatus for booting a clustered management system is provided where the configuration information required to boot the system is stored within the system itself. The techniques cope with several issues including finding the configuration data on the physical disk before the logical disk system is established, coping with replicated copies of configuration data, network partitions and disk drive failures that may prevent a booting node to have perfect knowledge of the state of the entire system, and active nodes modifying or moving configuration data while the booting node is searching for a consistent, correct copy of configuration data.

Abstract: Techniques are described for logically isolating data I/O requests from different operating systems (OSes) for a same multi-tenant storage system (MTSS). Techniques provide for OSes and the MTSS to obtain security tokens associated with the OSes. In an embodiment, an OS uses a security token to generate an authentication token based on the contents of a data input/output (I/O) request and sends the authentication token to the MTSS along with the data I/O request. When an MTSS receives such data I/O request, MTSS retrieves its own copy of the security token associated with the OS and generates its own authentication token based on the contents of the received data I/O request. If the authentication token generated by the MTSS matches the authentication token generated by the OS, then the data I/O request is successfully authenticated. Otherwise, if the authorization tokens fail to match, then the data I/O request has been compromised.

Abstract: Techniques are described for logically isolating data I/O requests from different operating systems (OSes) for a same multi-tenant storage system (MTSS). Techniques provide for OSes and the MTSS to obtain security tokens associated with the OSes. In an embodiment, an OS uses a security token to generate an authentication token based on the contents of a data input/output (I/O) request and sends the authentication token to the MTSS along with the data I/O request. When an MTSS receives such data I/O request, MTSS retrieves its own copy of the security token associated with the OS and generates its own authentication token based on the contents of the received data I/O request. If the authentication token generated by the MTSS matches the authentication token generated by the OS, then the data I/O request is successfully authenticated. Otherwise, if the authorization tokens fail to match, then the data I/O request has been compromised.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: Techniques are provided for assigning read requests to storage devices in a manner that reduces the likelihood that any storage device will become overloaded or underutilized. Specifically, a read-request handler assigns read requests that are directed to each particular item among the storage devices that have copies of the item based on how busy each of those storage devices is. Consequently, even though certain storage devices may have copies of the same item, there may be times during which one storage device is assigned a disproportionate number of the reads of the item because the other storage device is busy with read requests for other items, and there may be other times during which other storage device is assigned a disproportionate number of the reads of the item because the one storage device is busy with read request for other items.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: Techniques are provided for assigning read requests to storage devices in a manner that reduces the likelihood that any storage device will become overloaded or underutilized. Specifically, a read-request handler assigns read requests that are directed to each particular item among the storage devices that have copies of the item based on how busy each of those storage devices is. Consequently, even though certain storage devices may have copies of the same item, there may be times during which one storage device is assigned a disproportionate number of the reads of the item because the other storage device is busy with read requests for other items, and there may be other times during which other storage device is assigned a disproportionate number of the reads of the item because the one storage device is busy with read request for other items.

Abstract: A method and apparatus for booting a clustered management system is provided where the configuration information required to boot the system is stored within the system itself. The techniques cope with several issues including finding the configuration data on the physical disk before the logical disk system is established, coping with replicated copies of configuration data, network partitions and disk drive failures that may prevent a booting node to have perfect knowledge of the state of the entire system, and active nodes modifying or moving configuration data while the booting node is searching for a consistent, correct copy of configuration data.

Abstract: A method and apparatus for booting a clustered management system is provided where the configuration information required to boot the system is stored within the system itself. The techniques cope with several issues including finding the configuration data on the physical disk before the logical disk system is established, coping with replicated copies of configuration data, network partitions and disk drive failures that may prevent a booting node to have perfect knowledge of the state of the entire system, and active nodes modifying or moving configuration data while the booting node is searching for a consistent, correct copy of configuration data.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: A method of updating an extent map is described. The method includes providing in a memory an instance of a first version of the extent map, wherein the instance is referenced by an application. The extent map include entries. The method further includes storing, at each extent map entry, an offset from the beginning of a physical drive which is identified within said each extent map entry, providing a second version of the extent map, comparing the first version of the extent map with the second version of the extent map, in response to the comparing, determining that is at least on segment in the second version of the extent map that is different from a corresponding at least one segment in the first version of the extent map.

Abstract: Methods of hot-swapping a logical volume manager (LVM) and updating an associated extent map are presented. Methods for migrating a virtual machine running an application using an LVM from one physical machine to another physical machine are also presented. The LVM can be used by a database application or other applications in a single-node or multi-node environment. The LVM is shut down, version numbers for each segment of its associated extent map are saved, and a new LVM is started. The new LVM's extent map is compared with the old extent map, and segments in the LVM which have changed are selectively updated.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: Techniques are provided for assigning read requests to storage devices in a manner that reduces the likelihood that any storage device will become overloaded or underutilized. Specifically, a read-request handler assigns read requests that are directed to each particular item among the storage devices that have copies of the item based on how busy each of those storage devices is. Consequently, even though certain storage devices may have copies of the same item, there may be times during which one storage device is assigned a disproportionate number of the reads of the item because the other storage device is busy with read requests for other items, and there may be other times during which other storage device is assigned a disproportionate number of the reads of the item because the one storage device is busy with read request for other items.