摘要:
Disclosed is a technique for transferring data using multiple backup components. Responsibility for a portion of data is assigned to a first backup component. When a data update for the portion of data is received at the first backup component from a primary source, the data update is mirrored to a second backup component that is not assigned responsibility for the portion of data. Also disclosed is a technique for processing data updates with a group of backup components. It is determined that a new backup component is active. Near an end of a consistent transactions set formation period, responsibility for one or more portions of data are assigned to each backup component in the group and to the new backup component. During a next consistent transactions set formation period, data updates are processed with each backup component in the group and the new backup component. Moreover, disclosed is a technique for processing data updates with a group of backup components. It is determined that a first backup component in the group is no longer available. Portions of data for which the first backup component had been assigned responsibility are reassigned to each of the other backup components in the group.
摘要:
Disclosed are a system, a method, and a computer program product to optimize the overall latency of transferring data from peer computers to storage devices. The latency optimization occurs after a group of data is received and organized by the peer computers. The average amount of time to transfer data to each particular storage device from the peer computers is used to determine the assignment of data transfers between the peer computers. Each peer computer maintains continuously updated measurements of the average time to transfer data to each storage device. The updated transfer time measurements are based upon a moving average with adjustable weighting of past and present measurements enabling the system to adapt to changing conditions.
摘要:
Disclosed are a system, a method, and a computer program product to provide for the optimization of the output transfer load balance between the peer computers transferring data to one or more storage devices. The peer computers receive, organize and transfer the data to storage devices. The data set is composed of a plurality of data transfers. After an initial division of the data transfers between the two peers, each peer will have assigned responsibility for a number of data transfers. If the one of the peer computers completes offloading transactions earlier than the other peer, then the peer that is still transferring data will employ the other peer to execute a portion of the remaining data transfers. The operation of the system is symmetrical in that either peer may assist the other peer depending upon which peer has idle time. In addition the operation is autonomous and self-adjusting resulting in the peer nodes optimizing the size of the portion of data transfers that are reassigned during the operation of the invention resulting in the minimization of idle time for either peer. The self-adjusting feature allows the system to react to changing conditions that affect data transfer rates to the storage devices.
摘要:
A method of transmitting information from a primary storage control unit to a secondary storage control unit in an asynchronous data copying system. The method includes building multiple descriptor blocks for transmission from the primary storage control unit, and encrypting multiple payloads according to one of n encryption methods. In addition, the n encryption methods are associated with the primary storage control unit and n decryption keys relating to the n encryption methods are associated with the secondary storage control unit. An index to the n encryption keys is associated with the multiple descriptor blocks. The method further includes encrypting each of the payloads according to one of the n encryption methods and indicating, in the index associated with a selected descriptor block, which decryption key relates to the encryption method used for any payload associated with a select descriptor block. Upon transmission of a descriptor block from the primary storage control unit to the secondary storage control unit, the index is read and an appropriate decryption key is applied according to a decryption method to decrypt any payload associated with the descriptor block.
摘要:
Provided are a method, system, and program for maintaining consistency when mirroring data using different copy technologies. Update groups having updates to primary storage locations are formed using a first copy technology. The updates in the update groups are copied to secondary storage locations. Update groups having updates to primary storage locations are formed using a second copy technology, wherein the updates in the update groups are copied to secondary storage locations. Indication is made in a data structure of a time of an update in response to including the update in one of the update groups formed using the first copy technology. Indication is also made in the data structure of a time of the update group formed using the second copy technology.
摘要:
An apparatus, system, and method are disclosed for continuously protecting data. A mirror module mirrors a primary record set to a base record set. A log module accumulates each record change to the primary record set in a log. A change selection module selects a record change from the log. A change application module applies the selected record change to the base record set to form a recovered record set.
摘要:
A simulation system (30) for simulating an operation of an automotive vehicle includes an input (34) providing vehicle information and path information and a controller (38) having a vehicle computer model therein. The controller (38) is programmed to determine a rear side slip angle of a vehicle computer model, when the rear side slip angle is greater than a threshold, determine a look ahead scale factor, when the rear side slip angle is greater than the threshold, increase a look ahead point as a function of the look ahead scale factor, determining a steering wheel angle input to the computer model by comparing the look ahead point and the intended path, and operate the computer model with the steering wheel angle input, and generate an output in response to the vehicle model and the initial steering wheel input or the first steering wheel input.
摘要:
A simulation system (30) for simulating an operation of an automotive vehicle includes an input (34) providing vehicle information and path information and a controller (38) having a vehicle computer model therein. The controller (38) is programmed to determine an initial steering wheel angle input to the computer model; determine a first steering wheel angle input to the computer model at a time later than the initial steering wheel angle input by comparing a look ahead point and an intended path; when the vehicle model is understeering, operate the computer model with the initial steering wheel angle input until an error of the first steering wheel angle and the initial is decreasing; when the error decreases, operate the computer model with the first steering wheel angle input; and generate an output in response to the vehicle model and the initial steering wheel input or the first steering wheel input.
摘要:
Provided are a method, system and article of manufacture for switching. An indication is received of a failure of a primary storage subsystem at a switch, wherein the switch couples a host to the primary storage subsystem and a secondary storage subsystem. Subsequently, a command received from the host at the switch is directed to the secondary storage subsystem for completion.
摘要:
Provided are a method, system, and program for remote copying of updates to primary and secondary storage locations subject to a copy relationship. A first copy relationship is established between first and second storage locations in a first storage system and second storage system, respectively, wherein updates to the first storage locations are copied to the second storage locations. A second copy relationship is established between the first storage locations in the first copy relationship and third storage locations in a third storage system, wherein updates to the first storage locations are indicated in a first bitmap. A suspended third copy relationship is established between the second storage locations in the first copy relationship and the third storage locations, wherein updates to the second storage locations are indicated in a second bitmap. Updates are copied from the first or second storage locations to the third storage locations, wherein the first or second bitmap is capable of being used to determine updates for the first or second storage locations to copy to the third storage locations.