International Business Machines Corporation

Sudhir Maddali

Sanket Rathi

Kiran Kumar Anumalasetty

Yadagiri Rajaboina

Venkata N Anumula

Venkata N S Anumula

James P Allen

Purna Chandra Jasti

Nicholas S Ham

Phani K Ayyagari

Madhusudanan Kandasamy

PurnaChandra Rao Jasti

Vinod Kumar Boddukuri

Manish Sharma

Madhusudana R Thanugundala

Bhyrav M Mutnury

Bruce Gerard Mealey

James Anthony Pafumi

Phani Kumar V U Ayyagari

Stephen M Tee

Venkata Ns Anumula

Ramesh Kumar Marupaka

Embodiments include systems, methods, and computer program products to perform an operation for enabling multipath I/O for logical volume backed virtual disks through redundant virtual I/O servers (VIOSs) on a computing system. The operation generally includes creating, from a physical storage device, a logical volume on a first VIOS. The logical volume on the first VIOS is activated in a first access mode. The operation also includes importing the logical volume to a second VIOS. The logical volume on the second VIOS is activated in a second access mode different from the first access mode. The operation further includes mapping the logical volume on the first and second VIOSs as a backing storage device for at least one logical partition hosted on the computing system.

Supporting MPIO for logical volume backed virtual disks

An interface superpipe is implemented in a filesystem. A filesystem in a kernel, receives a command to open a file, the command issued in the execution of a process in an application. The file is determined to be on an interface disk. It is determined that a context does not exist for the process and, in response, an adapter queue is allocated for the process in a kernel memory and mapped into a process address space associated with the process. The context information of the process is saved in the kernel memory. The filesystem may be part of a system further comprising a processor, a storage, an interface adapter in communication with the storage and sharing a memory space with the processor, and an application in communication with the filesystem.

Transparent CAPI exploitation for legacy application

An approach to virtualizing a coherent memory hardware accelerator is provided comprising creating a segment table for a client logical partition (LPAR), wherein a virtual address space is reserved in the segment table, receiving an Input/Output (I/O) request to use the coherent memory hardware accelerator, generating an I/O operation associated with the I/O request, wherein the I/O operation is passed to the coherent memory hardware accelerator, receiving a map request from the coherent memory hardware accelerator, creating an entry in the reserved virtual address space in the segment table, creating a hardware page table map request for mapping a memory address associated with the client LPAR and returning the reserved virtual address space to the coherent memory hardware accelerator, wherein the coherent memory hardware accelerator has remote direct memory access to memory associated with the client LPAR for performing an acceleration of one or more processes.

Virtualizing coherent hardware accelerators

According to one embodiment of the present invention, a method is provided. The method may include a computer registering a first instance of a logical partition on a source server with a logical unit and placing a first persistent reservation on the logical unit, wherein the first persistent reservation indicates that only the first instance of the logical partition can hold a reservation on the logical unit. The method may further include the computer registering a second instance of the logical partition on a destination server with the logical unit and downgrading the first persistent reservation, such that the first and second instances of the logical partition can hold persistent reservations on the logical unit. The method may further include the computer placing, by one or more computer processors, a second persistent reservation on the logical unit.

Live partition mobility with shared persistent reservations

A method is disclosed for retrieving the reservation status information of a storage area network (SAN) device, a host transmits a persistent reservation in command with service action setting of 'read reservation' to a first LUN, wherein the host is connected to a port of the data storage server to which the LUN belongs. The host receives a message from the LUN. The host determines that the message is a success. The host sends to the LUN a persistent reservation in command with service action setting of 'read keys', responsive to a success message. The host determines that the LUN responds with a zero data length. The host determines the LUN is reserved with type 2 reservation, responsive to a determination that the LUN responds with a non-zero data length.

SCSI reservation status information on a SAN disk

A technique for operating a storage area network includes detecting an input/output operation failure associated with a logical unit number, which is associated with a first target port. The technique also includes determining, subsequent to the detected input/output operation failure, whether the logical unit number is associated with a second target port. Finally, the technique includes routing subsequent input/output operations for the logical unit number to the logical unit number via the second target port, in response to determining that the logical unit number is associated with the second target port.

Dynamically tracking logical units moving between input/output ports of a storage area network target

A method for selecting a path control module (PCM) for a logical unit number (LUN) associated with a host enabled to support multiple PCMs is provided. The method may include selecting a PCM associated with the LUN from a plurality of supported PCMs. The method may also include creating an entry in a configuration database or a configuration file associated with the host, whereby the entry maps the selected PCM with a unique ID associated with the LUN. The method may further include determining a unique ID associated with a hard disk. The method may include matching the unique ID with the created entry. The method may include selecting the PCM from the matched entry based on the matching. Additionally, the method may include loading a kernel extension corresponding to the selected PCM. The method may include configuring the LUN using the loaded kernel extension corresponding to the selected PCM.

Choosing a multipath I/O (MPIO) path control module (PCM) for a logical unit number (LUN) on a host that supports multiple PCMS

A method for continuous data transfer when a USB mass storage device is disconnected and reconnected is provided. The method may include monitoring state information from one or more mass storage devices, using a software driver to detect a change in state of the mass storage device on the computer. Active I/O transfers using the USB mass storage device are paused when the software driver detects that the USB mass storage device is detached from the computer. A configurable timer is started. The software drive may detect the attaching of a USB device. If, prior to the expiration of the timer, the software driver verifies that the USB mass storage device is the same that was previously attached to the computer, active I/O transfers are continued.

Growing community of inventors

Hyderabad Telangana, India

Sudhir Maddali