International Business Machines Corporation

Kalman Zvi Meth

Adnan M Agbaria

Michael Edward Factor

Julian Satran

Su-Hsuan Huang

William Joseph Ferrante

Patrick Francis Caffrey

William Gole Tuel, Jr

Demetrios K Michailaros

Anton Prenneis

Zorik Machulsky

Ronen Itshak Kat

Renato John Recio

Giora Biran

Jose Eduardo Moreira

Vadim Makhervaks

Vijay Krishnarao Naik

John Lewis Hufferd

Jan Civlin

Ben-Ami Yassour

Avishay Traeger

George Goldberg

Itai Nahshon

Eran Borovik

Shmuel Ben Yehuda

Miriam Allalouf

Doron Chen

Roger Kahn

Systems and methods for optimizing operation of a physical device in a virtualized computing environment are provided. The method comprises monitoring instructions issued by an application running on a virtual machine's (VM) operating system, wherein the VM is hosted by a hypervisor providing access to a physical device connected to a virtualized computing environment; wherein a device driver supported by the operating system issues one or more instructions to an emulated device supported by the hypervisor to control the physical device according to the issued instructions, wherein the emulated device's registers are implemented in memory of the hypervisor and the instructions issued by the device driver are stored in said registers, wherein the hypervisor handles the instructions, in response to learning that the instructions are stored in said registers.

Virtual device emulation via hypervisor shared memory

Machines, systems and methods for deploying one or more virtual machines on a host computing system, the method comprising: receiving mapping information from a data storage system, wherein the mapping information associates a first data chunk stored in the data storage system with a unique identifier; utilizing the mapping information to determine whether any copies of the first data chunk have already been loaded into a memory of the host computing system in association with deployment of a first virtual machine or a second virtual machine on the host computing system; and in response to determining that no copies of the first data chunk have already been loaded into the memory: retrieving the first data chunk from the data storage system; loading the first data chunk into the memory; and utilizing the first data chunk to deploy the first virtual machine on the host computing system.

Efficient loading of data into memory of a computing system

A method for deploying one or more virtual machines on a host computing system is provided. The method comprises receiving mapping information from a data storage system. The mapping information associates a first data chunk stored in the data storage system with a unique identifier to support deployment of a first virtual machine on a host computing system. Once the mapping information is received, the mapping information is utilized to determine whether any copies of the first data chunk have already been loaded into a memory of the host computing system in association with deployment of the first virtual machine or a second virtual machine on the host computing system. If no copies of the first data chunk have already been loaded into the memory, the first data chunk is retrieved from the data storage system, loaded into the memory, and utilized to deploy the first virtual machine on the host computing system.

A method for managing power consumption in a data storage system is provided. The method comprises receiving a first input/output (I/O) request identifying an I/O operation to be performed by a storage device; delaying scheduling of the first I/O request to manage amount of power consumed by servicing the first I/O request; and forwarding the first I/O request to a storage controller associated with the storage device. The storage controller schedules the first I/O request using a scheduling mechanism, and the storage device services the first I/O request according to the scheduling mechanism.

Managing power consumption and performance in a data storage system

A computer implemented method is disclosed, for energy-saving operation of a storage device with a read/write head. The method includes monitoring workload of the storage device, calculating current mean workload and adjusting seek speed of the read/write head of the storage device to one of a plurality seek speeds depending on the calculated current mean workload. The step of adjusting the seek speed of the read/write head includes adjusting the seek speed of the read/write head to be a first seek speed if the calculated current mean workload is below a first threshold, adjusting the seek speed of the read/write head to be a second seek speed if the calculated current mean workload is between the first threshold and a second threshold, and adjusting the seek speed of the read/write head to be the first seek speed if the calculated current mean workload is greater than the second threshold. A computer program product and a data processing system are also disclosed.

Energy-saving operation of a storage device

Provided are methods, apparatus and computer programs for recovery from failures affecting a server in a data processing environment in which a set of servers controls a client's access to a set of resource instances. Independent of any server failure, the client or a gateway is provided with an identification of both a primary server for accessing the resource and at least one secondary server for use as a backup server for accessing the same resource instance (for example, the same physical storage disk). The client or gateway connects to the primary server to perform resource access operations. Following a failure that affects availability of the primary server, the client or gateway connects to the previously identified secondary server to access the same resource instance. Provision of the identification of at least one backup secondary server (without requiring the 'trigger' of a failure) avoids the need to discover a new server as part of the recovery operation following a failure. Release of existing reservations using a reset operation, and re-reservation by the original initiator via a backup server, deals with any dangling reservations.

Methods, apparatus and computer programs for recovery from failures in a computing environment

A method and system for detecting and managing an error detected in an iSCSI (Internet Small Computer System Interface) PDU (Protocol Data Unit) by using a RDMA (Remote Direct Memory Access) dedicated receive error queue for error recovery.

Recovery from iSCSI corruption with RDMA ATP mechanism

A method and system for transmitting data along one or more communication channels to a receiving device having addressable memory units, the data having a known size and being split into two or more data packets each having a respective header and each sent along one of said communication channels to a respective memory unit. A respective final data packet to be sent along each communication channel is marked so as to be identifiable by a respective memory unit. For each memory unit receiving the respective final data packet, an interrupt is generated, the receiving device is informed how much data was received by the memory unit, and a cumulative amount of data received by all memory units is determined so as to allow the reading device to identify when no more data packets are to be transmitted.

System for computing cumulative amount of data received by all RDMA to determine when a complete data transfer has arrived at receiving device

The technique disclosed herein provides for simultaneously checkpointing all of the processes in a specified process group or family at the application level, and restoring those processes at a later time, optionally on a different machine, with the parent-child relationships restored intact. File descriptors that are shared among the processes at checkpoint time are restored to the family of processes such that the file descriptors are shared just as they were at the time of taking the checkpoint.

User-level checkpoint and restart for groups of processes

A checkpoint of a parallel program is taken in order to provide a consistent state of the program in the event the program is to be restarted. Each process of the parallel program is responsible for taking its own checkpoint, however, the timing of when the checkpoint is to be taken by each process is the responsibility of a coordinating process. During the checkpointing, various data is written to a checkpoint file. This data includes, for instance, in-transit message data, a data section, file offsets, signal state, executable information, stack contents and register contents. The checkpoint file can be stored either in local or global storage. When it is stored in global storage, migration of the program is facilitated. When a parallel program is to be restarted, each process of the program initiates its own restart. The restart logic restores the process to the state at which the checkpoint was taken.

System of performing checkpoint/restart of a parallel program

Method of performing checkpoint/restart of a parallel program

Program products for performing checkpoint/restart of a parallel program

A complete and consistent set of checkpoint files is captured and identified for use in restarting a parallel program. When each process of a parallel program takes a checkpoint, it creates a checkpoint file. The checkpoint file is named, and a part of that name includes a version number for the checkpoint file. When a parallel program is to be restarted, each process of the parallel program identifies its most current valid checkpoint file. It provides the version number of this file to a coordinating process. The coordinating process then decides which version of the checkpoint files is valid and complete for all of the processes of the parallel program participating in restart. Once this version number is determined, it is forwarded to the processes and the processes restore themselves using its corresponding checkpoint file having that particular version number.

Capturing and identifying a complete and consistent set of checkpoint files

A checkpoint of a process is taken in order to provide a consistent state of the process in the event the process is to be restarted. When the process is restarted, the process is placed in the state it was in when the checkpoint was taken. However, there are times when certain information has changed since the last checkpoint and it should not be restored. For example, if a process is restarted on a computing unit different from the one in which the checkpoint was taken, then environment variables associated with the new computing unit, such as the name of the computing unit, are not to be restored to the values they were before the checkpoint. In order to prevent this, one or more environment variables are adjusted, after the process is restored to the reflect the state they were in prior to restoration.

Restoring checkpointed processes including adjusting environment variables of the processes

A technique for statically linking an application process to a wrapper library employed in intercepting one or more calls invoked by the application process. The intercepted calls may comprise system calls or library calls. In a first link step, the application process is statically linked with at least the intercept library, and in one embodiment, all libraries associated with the application process except for the wrapper library. This first statically linking step creates a first module. Thereafter, at least one call invoked by the application process, and to be intercepted by the intercept library, is renamed. The renaming of the intercepted call is from its original name to a temporary name in the standard program library, the intercept library and the application program. This renaming step creates a second module that no longer contains the original name of the at least one intercepted call. The second linking step is to statically link the second module with the wrapper library, thereby creating an executable module wherein the application process is statically linked to all libraries while still providing for interception of the at least one system or library call within the executable.

Growing community of inventors

Netanya, Israel

Kalman Zvi Meth