746results about "Error avoidance" patented technology

A failure predicting unit predicts a failure in a hard disk device that forms a disk array. A data transferring unit transfers data from a failure-predicted hard disk device for which the failure is predicted by the failure predicting unit to a spare disk. A data deleting unit deletes the data from the failure-predicted hard disk device after the data transferring unit completes transferring the data.

A computer system includes a processor coupled to a DRAM through a memory controller. The processor switches the DRAM to a low power refresh mode in which DRAM cells are refreshed at a sufficiently low rate that data retention errors may occur. Prior to switching the DRAM to the low power refresh mode, the processor identifies a region of an array of DRAM cells that contains essential data that needs to be protected from such data retention errors. The processor then reads data from the identified region, and either the DRAM or the memory controller generates error checking and correcting syndromes from the read data. The syndromes are stored in the DRAM, and the low power refresh mode is then entered. Upon exiting the low power refresh mode, the processor again reads the data from the identified region, and the read data is checked and corrected using the syndromes.

A RAID controller performing a preemptive reconstruct of a redundant array of disks while the array is still fault-tolerant is disclosed. The controller receives user input specifying an error threshold. When a disk in the array (critical disk) exceeds the error threshold, the controller copies the critical disk data to a spare disk. After the copy completes, the controller replaces the critical disk with the spare disk in the array. The controller keeps the critical disk as part of the redundant array during the copy, i.e., continues to read and write the critical disk in response to user I/O requests. Hence, the array remains fault-tolerant during the preemptive reconstruct. In one embodiment, the controller automatically performs the reconstruct without user intervention. If the critical disk fails during the copy, the controller performs a conventional reconstruct to the spare disk starting where the copy left off.

A solid-state mass storage device and method of anticipating a failure of the mass storage device resulting from a memory device of the mass storage device reaching a write endurance limit. A procedure is then initiated to back up data to a second mass storage device prior to failure. The method includes assigning at least a first memory block of the memory device as a wear indicator, using other memory blocks of the memory device as data blocks for data storage, performing program/erase (P/E) cycles and wear leveling on the data blocks, subjecting the wear indicator to more P/E cycles than the data blocks, performing integrity checks and monitoring the bit error rate of the wear indicator, and taking corrective action if the bit error rate increases, including the initiation of the backup procedure and generating a request to replace the device.

A self healing file system is designed for proactive detection and containment of faults, errors, and corruptions, in order to enable in place (online) and non-intrusive recovery. For proactive fault detection, the file system maintains certain per-block metadata of each file system block. The per-block metadata includes a redundancy check, and for file system data blocks, an inode identifier, and an offset of the file system data block in the file including the file system data block. The redundancy check is used to detect and mark bad file system blocks. The inode identifier and offset is used for validating connectivity of the file system blocks to the inodes, and for tracing bad blocks to files that contain the bad blocks.

Disclosed is a system and method for caching data. A processor receives data from a host to modify a track in a first storage device. The processor stores a copy of the modified data in a cache and indicates in a second storage device the tracks for which there is modified data in cache. During data recovery operations, the processor processes the second storage device and data therein to determine the tracks for which there was modified data in cache. The processor then marks the determined tracks as failed to prevent data at the determined tracks in the first storage device from being returned in response to a read request until the failure is resolved. In further embodiments, in response to detecting a partial failure within the storage system, the processor would scan the cache to determine tracks for which there is modified data stored in the cache. The processor then stores in the second storage device information indicating the tracks having modified data in cache and schedules the destaging of the modified data from the cache to the first storage device. The processor is further capable of receiving and processing read/write requests directed to the first storage device before all the modified data is destaged from cache.

A shared memory controller is provided for controlling access to a shared memory by a plurality of processors. At least one device includes a storage area for storing a respective address range for each of a plurality of memory regions. The at least one device further includes a permission table containing, for each of the plurality of memory regions, read and write permission data for each of the plurality of processors. A memory fault detector is coupled to the at least one device and has an input for receiving a memory access request including a memory address, a processor identification and a read/write indicator. The memory fault detector includes logic for determining whether a memory access according to the memory access request would conflict with the read and write permission data in the permission table.

A method in a data processing system for minimizing read/write errors caused by impaired performance of a hard disk drive during runtime operation of the hard disk drive. The runtime operation includes an active mode during which read/write operations are conducted and a standby mode which occurs while no read/write operation is underway. First, at least one performance parameter of a hard disk drive is monitored during a standby mode of operation. Next, in response to detecting a degraded value of the at least one performance parameter, performing preventive recovery action only during the standby mode of operation, such that the performance parameter is restored to an acceptable value without interfering with hard disk drive operation during an active mode.

An integrated circuit, such as a microprocessor, which incorporates hardware mechanisms to prevent the circuitry from operating outside the proper bounds of design. The hardware circuitry prevents the microprocessor circuitry from being forced to operate at clock speeds that are greater than it is designed for, from operating at temperatures above or below that which it is designed for, and from being forced to operate at voltages that are above or below voltages that the microprocessor is designed to operate at.

In general, embodiments of the invention relate to reading data from and writing data to a storage system. Specifically, embodiments of the invention relate to a read only mode for a portion of a storage system. In one embodiment, a selective read-only mode for a portion of a storage system is implemented by monitoring a condition that may affect a subset of persistent storage in a storage system, by detecting the condition, by entering a read-only mode for the subset, and by enforcing a policy of processing write requests and read requests to the storage system, which includes processing the write requests without modifying user data stored on the subset and processing the read requests, including requests for user data stored on the subset.

A method effectively preventing a requesting node from unfencing and mounting a file system subsequent to a failure in a cluster file system having a plurality of active nodes. The method comprising first upgrading one active node in the cluster to function as a cluster manager node. The cluster manager is in communication with all nodes. The cluster manager is assigned manager responsibilities, in part, comprising first receiving an active status request from the node requesting to mount a file system. The cluster manager first queries the quorum nodes to determine whether each node considers the cluster manager to still have cluster management responsibilities for the file system. If a majority of quorum nodes consider the cluster manager to still have cluster management responsibilities for the file system then the cluster manager responds to the requesting node's active status request. Thereafter, the requesting node proceeds with mounting the file system.

A system for monitoring various support devices of a computer network is disclosed. The network has a monitoring computer with a monitoring program that monitors the devices. The monitoring program is used to configure a subordinate program. Using push technology, the subordinate program is installed on and is run on target computers in the network. The monitoring program monitors operating parameters and alarm signals from the devices. When the monitoring program determines that the devices can no longer support its load, the monitoring computers sends a shut down instruction to the affected target computers. The subordinate program executes a shutdown routine for the target computer based on the shutdown instruction sent from the monitoring program. The subordinate program has minimal or no graphical user interface on the target computer and requires no local configuration by the user of the target computer.

A method of reconfiguring a stream process in a distributed system includes the initial step of managing a stream process including one or more operators. The one or more operators are communicatively associated with one or more stream targets. The one or more operators use a partition function to determine the routing of messages to the one or more stream targets. The method includes the steps of determining a safe state within the stream process, and configuring a configuration state of the one or more operators during the safe state.

Techniques used to enhance the execution of long-running or complex software application instances and jobs on computing systems are disclosed herein. In one embodiment, a real time, self-predicting job resource monitor is employed to predict inadequate system resources on the computing system and failure of a job execution on the computing system. This monitor may not only determine if inadequate resources exist prior to execution of the job, but may also detect in real time if inadequate resources will be encountered during the execution of the job for cases where resource availability has unexpectedly decreased. If a resource deficiency is predicted on the executing computer system, the system may pause the job and automatically take corrective action or alert a user. The job may resume after the resource deficiency is met. Additional embodiments also integrate this resource monitoring capability with the adaptive selection of a computer system or application execution environment based on resource capability predictions and benchmarks.

Various embodiments are disclosed of a failure detection system for a solid-state data storage system that can experience difficulties, such as system failure or loss of data integrity, when it runs out of spare storage locations. Spare storage locations can be used by a solid-state data storage system to replace storage locations that have become defective. In one embodiment, a count is kept of the available spare storage locations in a system, or sub-system, and when the amount of available spare locations drops to a threshold value, an action can be taken to avoid the consequences of an impending failure. In other embodiments, the available spare storage locations are monitored by keeping track of the percentage of initially available spare locations still remaining, by keeping track of the rate of new spare locations being used, or by other techniques. In various embodiments, the early failure detection system responds to detection of a possible impending failure by taking one or more of a variety of actions, including, for example, sending an alert notification, enabling additional storage capacity, copying portions of the data stored in the system to other secure storage locations, shutting the system down, and taking no action.

A technique is described for controlling a storage system in which primary storage volumes and replication storage volumes are present. A boundary of a potential failure of the primary storage volumes and the replication storage volumes is determined, and using that boundary, replication storage volumes are assigned to assure that at least some of them are outside the failure boundary.

In general, embodiments of the invention relate to reading data from and writing data to a storage system. Specifically, embodiments of the invention relate to a read only mode for a portion of a storage system. In one embodiment, a selective read-only mode for a portion of a storage system is implemented by monitoring a condition that affects a subset of persistent storage in a storage system, by detecting the condition, by entering a read-only mode for the subset, and by enforcing a policy of processing write requests and read requests to the storage system, which includes processing the write requests without modifying user data stored on the subset and processing the read requests, including requests for user data stored on the subset.

A method, apparatus, and computer instructions for halting input/output error propagation in the logically partitioned data processing system. All components associated with the bridge are identified to form a set of failed components in response to detecting an error state in a bridge within a set of bridges in the logical partitioned data processing system. An identification of the failed components is stored in which the identification is used by each partition during a boot process.

Systems, methods, apparatus and software can implement a flexible I/O fence mechanism framework allowing clustered computer systems to conveniently use one or more I/O fencing techniques. Various different fencing techniques can be used, and fencing mechanism can be customized.

Network devices and systems relating to prevention of large-scale network failure and determining a probability of a large-scale network failure for a network. The network devices may control rerouting of network traffic from failed network paths to preventative paths with probabilities of failure below determined thresholds. The network devices monitor and process real time data for dynamic and proactive rerouting when large-scale network failure occurs or is likely to occur.

A method and system for checking health of information technology infrastructure based on log data, in one aspect, collect log data non-intrusively from a production system, said log data at least associated with transactions occurring in the production system and resource utilization of the production system, normalize said log data into a plurality of log data types, perform data regression analysis using said plurality of log data types to estimate resources consumed by each of said transactions and throughput of each of said transactions, and use a queuing model to predict performance of the information technology infrastructure under various workloads.

A method of predicting failures of data storage devices in a data storage network. In predicting failures, birth and/or health records of data storage devices in the data storage network are requested. The records are then scaled and thresholded and processed using a probabilistic neural network to classify the data storage devices. Based on the classification, an action is taken to improve the reliability and availability of the data storage network.