Abstract: A system and method for maintaining operation of a storage array with one or more failed storage devices and for quickly recovering when failing devices are replaced are provided. In some embodiments, the method includes receiving a data transaction directed to a volume and determining that a storage device associated with the volume is inoperable. In response to determining that the storage device is inoperable, a data extent is recorded in a change log in a storage controller cache. The data extent is associated with the data transaction and allocated to the storage device that is inoperable. The data transaction is performed using at least one other storage device associated with the volume, and data allocated to the storage device is subsequently reconstructed using the recorded data extent.

Abstract: The present invention is directed to a method for pre-emptive read reconstruction. In the method(s) disclosed herein, when a pre-emptive read reconstruction timer times out, if one or more drive read operations for providing requested stripe read data are still pending; and if stripe read data corresponding to the pending drive read operations may be constructed (ex.—reconstructed) based on the stripe read data received before the expiration of the timer, the pending drive read operations are classified as stale, but the pending drive read operations are still allowed to complete rather than being aborted, thereby promoting efficiency of the data storage system in situations when the data storage system includes an abnormal disk drive (ex.—a disk drive which endures random cycles of low read performance).

Abstract: A method for reading data from a data storage system is provided. The method comprises requesting a virtual data volume to access data from one or more data blocks in the data storage system; requesting a virtual protection information volume to access protection information associated with the data blocks; validating the data using the protection information; and providing the data to the host interface, in response to successful validation of the data. A method for writing data to a data storage system is also provided. The method comprises receiving data to be written to one or more data blocks in the data storage system, wherein the data is stored in a cache; generating protection information to be stored on a virtual protection information volume; requesting a virtual data volume to update the data blocks with the data; and requesting the virtual protection information volume to store the protection information.

Abstract: A method for validating data in a data storage system comprising associating a first data chunk with first check data and storing the first data chunk and the first check data on a first storage device. Additional associated data chunks of the first data and associated additional check data are stored on at least one of the first storage device or one or more additional storage devices. At least a portion of the first check data and at least a portion of the additional check data are stored to a second storage device, which is distinct from the first storage device and the additional storage devices. I/O access to the second storage device is minimized by retaining at least a portion of the first check data and at least a portion of the additional check data in a readily accessible storage medium, during servicing of a first I/O request.

Abstract: Disclosed is a method and system of determining a data block of a RAID level 6 stripe that has corrupted or incorrect data. For each data block of the stripe, a reconstructed data block is created using the other data blocks and the P syndrome data block. The reconstructed data block and the other data blocks are used to create a new Q syndrome data block. The new Q syndrome data block and the stored Q syndrome data block are compared. If the new Q syndrome data block and the stored Q syndrome data block match, the data block is marked as being suspected as having corrupted or incorrect data. This process is repeated for every data block in the stripe. If there is only a single suspected data block, the reconstructed data block is stored as a replacement of the suspect data block in the stripe.

Abstract: A method for reading data from a data storage system is provided. The method comprises requesting a virtual data volume to access data from one or more data blocks in the data storage system; requesting a virtual protection information volume to access protection information associated with the data blocks; validating the data using the protection information; and providing the data to the host interface, in response to successful validation of the data. A method for writing data to a data storage system is also provided. The method comprises receiving data to be written to one or more data blocks in the data storage system, wherein the data is stored in a cache; generating protection information to be stored on a virtual protection information volume; requesting a virtual data volume to update the data blocks with the data; and requesting the virtual protection information volume to store the protection information.

Abstract: A method for validating data in a data storage system comprising associating a first data chunk with first check data and storing the first data chunk and the first check data on a first storage device. Additional associated data chunks of the first data and associated additional check data are stored on at least one of the first storage device or one or more additional storage devices. At least a portion of the first check data and at least a portion of the additional check data are stored to a second storage device, which is distinct from the first storage device and the additional storage devices. I/O access to the second storage device is minimized by retaining at least a portion of the first check data and at least a portion of the additional check data in a readily accessible storage medium, during servicing of a first I/O request.

Abstract: Disclosed is a system and a method for implementing trace buffers in a computer program. A trace facility monitors operation of the computer program in real time. As the code is executed, error-related events occur and are divided into at least three components, including errors, warnings, and messages. Records of these events are stored in the trace buffers. Each task, process, or component of the embedded system that is traced may have an independent set of trace buffers. Unique events eliminate the confusion as to where or when an event occurs in a system. Separate trace buffers for each component of the embedded system ensure that no component consumes buffer resources needed by other components. The trace facility may be embedded in the code in a transparent manner and may be utilized to locate errors on-site.