Abstract: A technique for failure monitoring and recovery of a first application executing on a first virtual machine includes storing machine state information during execution of the first virtual machine at predetermined checkpoints. An error message that includes an application error state at a failure point of the first application is received, by a hypervisor, from the first application. The first virtual machine is stopped in response to the error message. The hypervisor creates a second virtual machine and a second application from the stored machine state information that are copies of the first virtual machine and the first application. The second virtual machine and the second application are configured to execute from a checkpoint preceding the failure point. In response to receipt of a failure interrupt by the second application, one or more recovery processes are initiated in an attempt to avert the failure point.

Abstract: A virtual machine backup method includes utilizing a log to indicate updates to memory of a virtual machine when the updates are evicted from a cache of the virtual machine. A guard band is determined that indicates a threshold amount of free space for the log. A determination is made that the guard band will be or has been encroached upon corresponding to indicating an update in the log. A backup image of the virtual machine is updated based, at least in part, on a set of one or more entries of the log, wherein the set of entries is sufficient to comply with the guard band. The set of entries is removed from the log.

Abstract: In an approach to allocating hypervisor resources for virtual machine deployment, one or more computer processors determine one or more hierarchically grouped computing resources within a hypervisor. The one or more computer processors receive a selection of one or more hierarchically grouped computing resources. The one or more computer processors apply deployment constraints for a workload to the selected one or more hierarchically grouped computing resources. The one or more computer processors determine, based, at least in part, on the deployment constraints for the workload, one or more computing resources from the one or more hierarchically grouped computing resources.

Abstract: In an approach to allocating hypervisor resources for virtual machine deployment, one or more computer processors determine one or more hierarchically grouped computing resources within a hypervisor. The one or more computer processors receive a selection of one or more hierarchically grouped computing resources. The one or more computer processors apply deployment constraints for a workload to the selected one or more hierarchically grouped computing resources. The one or more computer processors determine, based, at least in part, on the deployment constraints for the workload, one or more computing resources from the one or more hierarchically grouped computing resources.

Abstract: A primary processing unit entitlement is determined for a logical partition. A smaller secondary processing unit entitlement is also determined. A partition manager allocates primary processing units to the logical partition from a primary shared processor pool, and the logical partition is activated. The secondary processing units are reserved for the logical partition from a secondary shared processor pool, and the logical partition can be relocated to the secondary shared processor pool in response to a condition such as a hardware failure. The logical partition can continue to process its workload with the fewer processor resources, and can be restored to the primary processing unit entitlement.

Abstract: A technique for failure monitoring and recovery of a first application executing on a first virtual machine includes storing machine state information during execution of the first virtual machine at predetermined checkpoints. An error message that includes an application error state at a failure point of the first application is received, by a hypervisor, from the first application. The first virtual machine is stopped in response to the error message. The hypervisor creates a second virtual machine and a second application from the stored machine state information that are copies of the first virtual machine and the first application. The second virtual machine and the second application are configured to execute from a checkpoint preceding the failure point. In response to receipt of a failure interrupt by the second application, one or more recovery processes are initiated in an attempt to avert the failure point.

Abstract: A partition manager relocates a logical partition from a primary shared processor pool to a secondary shared processor pool in response to a predetermined condition, such as a hardware failure. The relocated logical partition is allocated a smaller quantity of processing units from the secondary pool than it was allocated from the primary pool. A quantity of processing units reserved for a second logical partition is identified in the secondary shared processor pool, and a portion of those reserved processing units are allocated to the relocated logical partition. The reserved processing units may be redistributed among multiple relocated logical partitions.

Abstract: A technique for managing a data network includes monitoring data transfer rates and data transfer thresholds for data transferred between storage and an application. Feedback on the suitability of the data transfer rate is collected from the application. A data transfer threshold for the application is changed based on the monitored data transfer rate and the collected feedback.

Abstract: Disclosed is a computer system (100) comprising a processor unit (110) adapted to run a virtual machine in a first operating mode; a cache (120) accessible to the processor unit, said cache including a cache controller (122); and a memory (140) accessible to the cache controller for storing an image of said virtual machine; wherein the processor unit is adapted to create a log (200) in the memory prior to running the virtual machine in said first operating mode; the cache controller is adapted to transfer a modified cache line from the cache to the memory; and write only the memory address of the transferred modified cache line in the log; and the processor unit is further adapted to update a further image of the virtual machine in a different memory location, e.g. on another computer system, by retrieving the memory addresses stored in the log, retrieve the modified cache lines from the memory addresses and update the further image with said modifications.

Abstract: Disclosed is a computer system (100) comprising a processor unit (110) adapted to run a virtual machine in a first operating mode; a cache (120) accessible to the processor unit, said cache comprising a plurality of cache rows (1210), each cache row comprising a cache line (1214) and an image modification flag (1217) indicating a modification of said cache line caused by the running of the virtual machine; and a memory (140) accessible to the cache controller for storing an image of said virtual machine; wherein the processor unit comprises a replication manager adapted to define a log (200) in the memory prior to running the virtual machine in said first operating mode; and said cache further includes a cache controller (122) adapted to periodically check said image modification flags; write only the memory address of the flagged cache lines in the defined log and subsequently clear the image modification flags.

Abstract: Disclosed is a computer system (100) comprising a processor unit (110) adapted to run a virtual machine in a first operating mode; a cache (120) accessible to the processor unit, said cache including a cache controller (122); and a memory (140) accessible to the cache controller for storing an image of said virtual machine; wherein the processor unit is adapted to create a log (200) in the memory prior to running the virtual machine in said first operating mode; the cache controller is adapted to transfer a modified cache line from the cache to the memory; and write only the memory address of the transferred modified cache line in the log; and the processor unit is further adapted to update a further image of the virtual machine in a different memory location, e.g. on another computer system, by retrieving the memory addresses stored in the log, retrieve the modified cache lines from the memory addresses and update the further image with said modifications.

Abstract: A partition manager relocates a logical partition from a primary shared processor pool to a secondary shared processor pool in response to a predetermined condition, such as a hardware failure. The relocated logical partition is allocated a smaller quantity of processing units from the secondary pool than it was allocated from the primary pool. A quantity of processing units reserved for a second logical partition is identified in the secondary shared processor pool, and a portion of those reserved processing units are allocated to the relocated logical partition. The reserved processing units may be redistributed among multiple relocated logical partitions.

Abstract: A computer system comprises a processor unit arranged to run a hypervisor running one or more virtual machines, a cache connected to the processor unit and comprising a plurality of cache rows, each cache row comprising a memory address, a cache line and an image modification flag and a memory connected to the cache and arranged to store an image of at least one virtual machine. The processor unit is arranged to define a log in the memory and the cache further comprises a cache controller arranged to set the image modification flag for a cache line modified by a virtual machine being backed up, periodically check the image modification flags and write only the memory address of the flagged cache rows in the defined log. The processor unit is further arranged to monitor the free space available in the defined log and to trigger an interrupt if the free space available falls below a specific amount.

Abstract: Disclosed is a computer system (100) comprising a processor unit (110) adapted to run a virtual machine in a first operating mode; a cache (120) accessible to the processor unit, said cache comprising a plurality of cache rows (1210), each cache row comprising a cache line (1214) and an image modification flag (1217) indicating a modification of said cache line caused by the running of the virtual machine; and a memory (140) accessible to the cache controller for storing an image of said virtual machine; wherein the processor unit comprises a replication manager adapted to define a log (200) in the memory prior to running the virtual machine in said first operating mode; and said cache further includes a cache controller (122) adapted to periodically check said image modification flags; write only the memory address of the flagged cache lines in the defined log and subsequently clear the image modification flags.

Abstract: A primary processing unit entitlement is determined for a logical partition. A smaller secondary processing unit entitlement is also determined. A partition manager allocates primary processing units to the logical partition from a primary shared processor pool, and the logical partition is activated. The secondary processing units are reserved for the logical partition from a secondary shared processor pool, and the logical partition can be relocated to the secondary shared processor pool in response to a condition such as a hardware failure. The logical partition can continue to process its workload with the fewer processor resources, and can be restored to the primary processing unit entitlement.

Abstract: Disclosed is a system for controlling write actions to a plurality of data storage devices, the system comprising a plurality of write caches, wherein each cache is associated with a set of said data storage devices; and a controller adapted to issue write permissions to said data storage devices, said write permissions including a permission to perform a data destage operation from a cache to a data storage device; wherein each cache has a first performance score expressed as the difference between the number of data destage operations said cache has in flight and the maximum number of data destage actions said cache is permitted to issue in parallel; and wherein the controller is adapted to offer a data destage operation permission to the cache in said plurality of caches associated with the highest first performance score.

Abstract: Two or more processes for executing a source application are emulated using: a virtual trampoline memory in which each emulated process has a respective private trampoline memory; and a shared code heap memory. Each emulated process only sees the shared code heap and its respective private trampoline memory. A respective equivalent target instruction fragment for writing to the code heap is generated for each of multiple source instruction fragments from the application, each target instruction fragment being indexed by its physical address in the code heap. Each of at least one jump instruction in the fragment is replaced with a jump to a corresponding slot in the virtual trampoline memory. A trap is written to each corresponding private trampoline slot, each trap adapted to be replaced by a jump to an address in the code heap corresponding to the jump destination.

Abstract: A technique for managing a data network includes monitoring data transfer rates and data transfer thresholds for data transferred between storage and an application. Feedback on the suitability of the data transfer rate is collected from the application. A data transfer threshold for the application is changed based on the monitored data transfer rate and the collected feedback.

Abstract: A technique of operating a data processing system, includes logging addresses for cache lines modified by a producer core in a data array of a producer cache to create a high-availability (HA) log for the producer core. The technique also includes moving the HA log directly from the producer cache to a consumer cache of a consumer core and moving HA data associated with the addresses of the HA log directly from the producer cache to the consumer cache. The HA log corresponds to a cache line that includes multiple of the addresses. Finally, the technique includes processing, by the consumer core, the HA log and the HA data for the data processing system.

Abstract: A technique of operating a data processing system, includes logging addresses for cache lines modified by a producer core in a data array of a producer cache to create a high-availability (HA) log for the producer core. The technique also includes moving the HA log directly from the producer cache to a consumer cache of a consumer core and moving HA data associated with the addresses of the HA log directly from the producer cache to the consumer cache. The HA log corresponds to a cache line that includes multiple of the addresses. Finally, the technique includes processing, by the consumer core, the HA log and the HA data for the data processing system.