Abstract: A computer-implemented method for detecting data storage errors includes storing first data in a first block corresponding to a first virtual volume, storing second data in a second block corresponding to a second virtual volume, generating parity information for the first data and the second data, and storing the parity information in non-volatile memory at a location corresponding to the logical block address to produce stored parity information. A system and computer program product corresponding to the above method are also disclosed herein.

Abstract: A method, computer program product, and computer system are provided for testing drives in a redundant array of independent disks (RAID) array. The method includes: mirroring data from a selected drive to be tested in a RAID array to spare storage space in the RAID array; and, once the data is successfully mirrored, testing the selected drive to identify a preemptive failure of the selected drive. The RAID may be a traditional RAID (TRAID) array and the spare space may be a spare physical drive independent of array drive members. The RAID array may alternatively be a distributed RAID (DRAID) array and the spare space may be spare capacity spread through the array drive members.

Abstract: A method, system, and computer program product for managing a storage system, comprising: analyzing an access request for a first storage block of the set of storage blocks; in response to the access request comprising a read request: in response to the first storage block residing in the cache: processing the read request from the cache; promoting the first storage block within the cache; and destaging the first storage block to the storage device with the first compression ratio; and in response to the first storage block not residing in the cache: processing the read request from the storage device; and copying the first storage block to the cache; in response to the access request comprising a write request: writing the first storage block to the cache; and destaging the first storage block to the storage device using the first compression ratio.

Abstract: A method, system, computer program product and computer program for managing a storage system, the storage system comprising a first storage device, a second storage device, a source storage device, a target storage device, and a cache, the method comprising: receiving a first host access request for a data block on the first storage device; receiving a mapping between the source storage device and the target storage device; and in response to the first host access request and the mapping: accessing a corresponding data block on the second storage device; and updating metadata for the cache.

Abstract: A system for managing a storage array in a storage system may include an analysis component for analyzing a set of compression ratios used for a set of storage blocks written on a first storage device and a second storage device to determine a pattern. The system may include a determination component for determining, responsive to the pattern, a first compression ratio and a second compression ratio; the first compression ratio may be different from the second compression ratio. The system may include a data read/write component for writing a storage block to the first storage device with the first compression ratio and writing the storage block to the second storage device with the second compression ratio.

Abstract: Disclosed are techniques for defragmentation in deduplication storage systems. Machine language determines using deduplication metadata that at least some of an incoming input/output stream is a duplicate of at least part of a source volume whose physical locations of its stored data are fragmented in backend storage. Subsequently, defragmentation is carried out on the stored data by using the incoming input/output stream to write the data into sequential chunks at new physical locations in the backend storage and updating the source volume location mappings to the new physical locations.

Abstract: Disclosed are techniques for defragmentation in deduplication storage systems. Machine language determines using deduplication metadata that at least some of an incoming input/output stream is a duplicate of at least part of a source volume whose physical locations of its stored data are fragmented in backend storage. Subsequently, defragmentation is carried out on the stored data by using the incoming input/output stream to write the data into sequential chunks at new physical locations in the backend storage and updating the source volume location mappings to the new physical locations.

Abstract: Garbage collection is performed for a virtualized storage system whose virtual address space is addressed in extents. Valid data in source extents is copied via a cache into destination extents. Once all valid data in a source extent is copied into one or more destination extents, the source extent may be reused. A source extent is released for reuse only after the one or more destination extents that received the valid data copied from the source extent are determined to be full, and the valid data copied from the source extent to the destination extent via the cache is flushed out of the cache.

Abstract: Garbage collection is performed for a virtualized storage system whose virtual address space is addressed in extents. Valid data in source extents is copied via a cache into destination extents. Once all valid data in a source extent is copied into one or more destination extents, the source extent may be reused. A source extent is released for reuse only after the one or more destination extents that received the valid data copied from the source extent are determined to be full, and the valid data copied from the source extent to the destination extent via the cache is flushed out of the cache.

Abstract: Garbage collection is performed for a virtualized storage system whose virtual address space is addressed in extents. Valid data in source extents is copied via a cache into destination extents. Once all valid data in a source extent is copied into one or more destination extents, the source extent may be reused. A source extent is released for reuse only after the one or more destination extents that received the valid data copied from the source extent are determined to be full, and the valid data copied from the source extent to the destination extent via the cache is flushed out of the cache.

Abstract: An architecture for error log processing is provided. Each error log is given a defined priority and mapped to an error recovery procedure (ERP) to be run if the log is seen. The system has a plurality of software layers to process the errors. Each software layer processes the error independently. Errors are reported to a higher software stack when error recovery fails from the lower stack ERPs and recovery is non-transparent. If the system host identified for error processing fails, the control of the ERP is transferred during the failover process. Non-obvious failed component isolating ERPs are grouped to be run together to assist in isolating the failed component. Prioritization of the error systems may be based on a plurality of criteria. ERPs are assigned to run within a particular software stack.

Abstract: An architecture for error log processing is provided. Each error log is given a defined priority and mapped to an error recovery procedure (ERP) to be run if the log is seen. The system has a plurality of software layers to process the errors. Each software layer processes the error independently. Errors are reported to a higher software stack when error recovery fails from the lower stack ERPs and recovery is non-transparent. If the system host identified for error processing fails, the control of the ERP is transferred during the failover process. Non-obvious failed component isolating ERPs are grouped to be run together to assist in isolating the failed component. Prioritization of the error systems may be based on a plurality of criteria. ERPs are assigned to run within a particular software stack.