Abstract:
A configuration is generated for a software that is to be deployed for providing high service availability to satisfy configuration requirements. One or more configuration patterns are identified, each of which specifies a set of attribute values and an actual recovery action for a failed component as a configuration option of the software. The unchangeable attribute values of the software are matched with the configuration patterns to obtain a matching configuration pattern, whose actual recovery action incurs a smallest component failure recovery impact zone. The matching configuration pattern is selected as at least a portion of the configuration of the software. Then the changeable attribute values of the software are set to the corresponding attribute values of the matching configuration pattern to satisfy the configuration requirements.
Abstract:
A host (1) and a storage system (2) each keep a shared identifier indicating a state of a system. The storage system (2) acquires, at update of data, a data pair including data for a change through processing of the host (1) and data before the update. The storage system (2) relates the data pair to a shared identifier. When the host (1) indicates an identifier, the storage system (2) restores data using the data pair.
Abstract:
A wireless communication system utilizes system frame numbers (SFNs) upon which to base identification of frames of information transmitted by the communication system, as well as for expressing timeout values associated with process-set timers. The wireless communication system comprises a first (active) unit (40) which executes an operational process (OP), as well as a second (standby) unit (42) which executes the operational process in redundant manner with the first unit. The operational process sets a timer by computing an expiration system frame number to be used for determining a timeout value. The timer expires when a current system frame number reaches the calculated expiration system frame number. The SFN-based timeout values of the present invention are easily accessible and easily re-established upon reset and resynchronization of one of the redundant units.
Abstract:
A cluster implements a virtual disk system that provides each node of the cluster access to each storage device of the cluster. The virtual disk system provides high availability such that a storage device may be accessed and data access requests are reliably completed even in the presence of a failure. To ensure consistent mapping and file permission data among the nodes, data are stored in a highly available cluster database. Because the cluster database provides consistent data to the nodes even in the presence of a failure, each node will have consistent mapping and file permission data. A cluster transport interface is provided that establishes links between the nodes and manages the links. Messages received by the cluster transports interface are conveyed to the destination node via one or more links. The configuration of a cluster may be modified during operation. Prior to modifying the configuration, a reconfiguration procedure suspends data access requests and waits for pending data access requests to complete. The reconfiguration is performed and the mapping is modified to reflect the new configuration. The node then updates the internal representation of the mapping and resumes issuing data access requests.
Abstract:
A cluster implements a virtual disk system that provides each node of the cluster access to each storage device of the cluster. The virtual disk system provides high availability such that a storage device may be accessed and data access requests are reliably completed even in the presence of a failure. To ensure consistent mapping and file permission data among the nodes, data are stored in a highly available cluster database. Because the cluster database provides consistent data to the nodes even in the presence of a failure, each node will have consistent mapping and file permission data. A cluster transport interface is provided that establishes links between the nodes and manages the links. Messages received by the cluster transports interface are conveyed to the destination node via one or more links. The configuration of a cluster may be modified during operation. Prior to modifying the configuration, a reconfiguration procedure suspends data access requests and waits for pending data access requests to complete. The reconfiguration is performed and the mapping is modified to reflect the new configuration. The node then updates the internal representation of the mapping and resumes issuing data access requests.
Abstract:
A fault tolerant multiple network server system in which multiple servers concurrently act as back-up servers for each other even while they are providing their own server services to the system. Rather than having an unused server monitoring for failure of a primary server and taking over control, each is act upon the network, but when its partner should fail, it assumes control of these partner servers storage subsystem. In this way, processing power of both servers is available during normal operation, but they each provide back-up capability for the other.
Abstract:
A system and method are disclosed to organize computer software operating in a distributed system of computers, so that its recovery from a failure of either the software or the hardware occurs before the failure becomes operationally visible. The software is made to recover from the failure and reprocess or reject the stimulus such that the result is available to the user of the system within the specified response time for that type of stimulus.
Abstract:
The method and apparatus for maintaining active sessions between communicating logical units (10, 40) in a computer network when an application system fails without having to re-establish the active sessions, are carried out by activating a persistent session capability at one of the logical units. Thus, the active sessions can be suspended and maintained while attempts at recovery are made. Recovery attempts include restarting the failed application or switching the suspended sessions to an alternate instance of the logical unit (10). The suspended sessions are re-synchronized with the application system and session activity is resumed.
Abstract:
The method and apparatus for maintaining active sessions between communicating logical units (10, 40) in a computer network when an application system fails without having to re-establish the active sessions, are carried out by activating a persistent session capability at one of the logical units. Thus, the active sessions can be suspended and maintained while attempts at recovery are made. Recovery attempts include restarting the failed application or switching the suspended sessions to an alternate instance of the logical unit (10). The suspended sessions are re-synchronized with the application system and session activity is resumed.