Abstract: A method and system of a host device hosting multiple workloads for controlling flows of I/O requests directed to a storage device is disclosed. In one embodiment, a type of a response from the storage device reacting to an I/O request issued by an I/O stack layer of the host device is determined. Then, a workload associated with the I/O request is identified among the multiple workloads based on the response to the I/O request. Further, a maximum queue depth assigned to the workload is adjusted based on the type of the response, where the maximum queue depth is a maximum number of I/O requests from the workload which are concurrently issuable by the I/O stack layer.

Abstract: The present invention relates to managing I/O requests in a storage system. By dynamically changing the scheduling parameters to achieve optimal turn around time for I/O requests pending for processing at a component in the storage system. The scheduling parameters are changed based on a feedback mechanism. The turn around time of the I/O request are calculated as the ratio of I/O request processing rate and the average number of I/O requests in the component.

Abstract: The invention relates to management of a plurality of I/O requests in a storage system. The host interface module is configured to receive a plurality of I/O request which includes an associated priority; create an I/O request queue for each associated priority; define a threshold value for the queue length for each of the plurality of I/O request queues; and determine if the queue length for one of the plurality of the I/O request queue corresponding to the associated priority is less than the defined threshold value for the queue length for the one of the plurality of the I/O request queues. If the queue length of the one of the plurality of I/O request queues is more than the defined threshold value for the queue then the host interface module is further configured to rejecting the I/O request and sending a queue full message; wherein the threshold value for the queue length is based on the processing rate of the I/O requests in the plurality of the I/O request queues.

Abstract: A method of recovering from an operating system crash or failure in a first memory. Upon detecting the crash or failure, a second memory provided as auxiliary memory to the first memory and being of equal size to the first memory is initialized, the operating system is booted in the second memory, content of the first memory is dumped to a dump storage device, and the first memory is prepared for use as auxiliary memory.

Abstract: A method and system for optimizing network I/O throughput is disclosed. In one embodiment, a method for optimizing an input/output (I/O) throughput for a storage network comprises measuring a service time for a storage device of the storage network in completing an I/O request serviced by a storage driver. The method also comprises determining a status of an I/O performance between the storage driver and the storage device by comparing the service time with an expected service time for the storage device in completing the I/O request, where the expected service time is calculated based on a type of the storage device and a size of the I/O request. The method further comprises adjusting a maximum queue depth associated with the storage device based on the status of the I/O performance.

Abstract: Provided is computer implemented method for logging system events, comprising: allocating a memory area for a log; receiving data indicative of a log event; storing said data in said memory area; synchronising data in said memory area to a log file stored in non-volatile storage, the non-volatile storage and the memory area being inaccessible to a user or an administrator.

Abstract: The invention relates to a method for determining device criticality in a computer system comprising the steps of building a component hierarchy graph using computer configuration information; labeling the nodes of component hierarchy graph with redundancy attribute; traversing the component hierarchy graph; and determining whether the device loses an access path by inspecting the redundancy attributes within the component hierarchy graph. Furthermore, one of a plurality of severity levels is assigned to each identified affected resource based on predetermined criteria. The severity levels include a low severity level, a medium severity level, and a high severity level. Each severity level represents degree of impact to the computer system if functionality of the identified affected resource became unavailable.

Abstract: A method for determining the criticality of a device in a multi-path computer configuration comprising the steps of: traversing a directed acyclic graph representing a platform hierarchy; and determining paths within the directed acyclic graph affected by the removal of the device. A computer system comprising a directed acyclic graph data structure representing a platform hierarchy; and a control arrangement for traversing the directed acyclic graph to determining paths therein affected by removal of a device.

Abstract: Embodiments of the invention relate to a data processing system and method for supporting dynamically assigning devices within a virtualisation environment.

Abstract: A system and method for flexible device driver resource allocation is disclosed. In one embodiment, a method for allocating device driver resources in a data processing system includes statically allocating hardware resource pools to device drivers on a rigid basis during initialization of the data processing system, and dynamically altering the allocated hardware resource pools to the device drivers based on parameters associated with utilization of the allocated hardware resource pools during run-time.

Abstract: The invention relates to a method for determining device criticality in a computer system comprising the steps of building a component hierarchy graph using computer configuration information; labeling the nodes of component hierarchy graph with redundancy attribute; traversing the component hierarchy graph; and determining whether the device loses an access path by inspecting the redundancy attributes within the component hierarchy graph. Furthermore, one of a plurality of severity levels is assigned to each identified affected resource based on predetermined criteria. The severity levels include a low severity level, a medium severity level, and a high severity level. Each severity level represents degree of impact to the computer system if functionality of the identified affected resource became unavailable.

Abstract: A method, a system and a computer program for determining device criticality during SAN reconfiguration operations comprising the steps of building the SAN connectivity graph and mapping the reconfiguration on SAN connectivity graph; locating the affected host systems; and determining the device criticality for each of the affected host systems. The hosts systems may also be provided with impact analysis agents to generate device criticality on host systems and a central agent to aggregate the device criticality from impact analysis agent and provide feedback to data center administrator.

Abstract: The method, apparatus and system of an I/O forwarding technique for multi-interrupt capable I/O devices are disclosed. In one embodiment, a method of transferring an I/O request in a cache-coherent non-uniform memory access (ccNUMA) computer system including multiple cells (e.g., each cell may include multiple processors) that are connected via a system interconnect, includes receiving an I/O request from one of the multiple processors associated with one of the multiple cells in the ccNUMA computer system, associating a processor, corresponding to a multi-interrupt capable I/O interface that is servicing the I/O request, located in the one of the multiple cells as a lead processor, and executing an I/O initiation path and a completion path associated with the received I/O request on the lead processor upon associating the lead processor corresponding to the multi-interrupt capable I/O interface.

Abstract: Embodiments provide a data processing system comprising at least one hard partition comprising a plurality of virtual partitions; each of the virtual partitions comprising respective virtual address spaces accessible via a memory access means for relating virtual addresses to real addresses of a real memory; wherein each virtual address space comprises respective unique virtual addresses.

Abstract: A method and apparatus are disclosed for storing data in a computer system 101 which data from a first portion of a system memory 117 is stored in a secondary memory 105; the first portion of the system memory 117 is allocated for subsequent use by an operating system (OS); the OS is rebooted and run using the allocated memory; and data from a remaining portion of the system memory 117 is stored in the secondary memory 105.

Abstract: A method and system for processing an input/output request on a multiprocessor computer system comprises pinning a process down to a processor issuing the input/output request. An identity of the processor is passed to a device driver which selects a device adapter request queue whose interrupt is bound to the identified processor and issues the request on that queue. The device accepts the request from the device adapter, processes the request and raises a completion interrupt to the identified processor. On completion of the input/output request the process is un-pinned from the processor. In an embodiment the device driver associates a vector of the identified processor with the request and the device, on completion of the request, interrupts the processor indicated by the vector.

Abstract: A method of recovering from an operating system crash or failure in a first memory. Upon detecting the crash or failure, a second memory provided as auxiliary memory to the first memory and being of equal size to the first memory is initialized, the operating system is booted in the second memory, content of the first memory is dumped to a dump storage device, and the first memory is prepared for use as auxiliary memory.