International Business Machines Corporation

Netapp, Inc.

Somasundaram Krishnasamy

Douglas J Griffith

Brian Dennis McKean

Adekunle Bello

Aruna Yedavilli

Yanling Qi

Angela Astrid Jaehde

Stephen A Schlachter

A method and system for synchronizing caches after reboot are described. In a cached environment, a host server stores a cache counter associated with the cache, which can be stored in the cache itself or in another permanent storage device. When data blocks are written to the cache, metadata for each data block is also written to the cache. This metadata includes a block counter based on a value of the cache counter. After a number of data operations are performed in the cache, the value of the cache counter is updated. Then, each data block is selectively updated based on a comparison of the value of the cache counter with a value of the block counter in the metadata for the corresponding data block.

System and method for synchronizing caches after reboot

Embodiments comprise a plurality of computing devices that dynamically intercept process application I/O errors. Various embodiments comprise two or more computing devices, such as two or more servers, each having access to a shared data storage system. An application may be executing on the first computing device and performing an I/O operation when an I/O error occurs. The first computing device may intercept the I/O error, rather than passing it back to the application, and prevent the error from affecting the application. The first computing device may complete the I/O operation, and any other pending I/O operations not written to disk, via an alternate path, perform a checkpoint operation to capture the state of the set of processes associated with the application, and transfer the checkpoint image to the second computing device. The second computing device may resume operation of the application from the checkpoint image.

Obviation of recovery of data store consistency for application I/O errors

A method, programmed medium and system are disclosed which provide for end-to-end QoS for a set of processes that comprise a workload over nfs. A set of processes that comprise a workload such as the processes of a WPAR, or an entire LPAR are given a class designation and assigned priority/limits. The data are then passed to the server which allocates resources based on the sum total of all the current classes and their priorities and/or limits. This requires re-engineering the nfs client code to be workload-aware and the nfs server code to accommodate the resource allocation and prioritization needs of the nfs clients.

Server resource allocation

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Austin, TX, United States of America

Somasundaram Krishnasamy