Abstract: Estimating a level of concurrency is provided. An estimated level of concurrency of a device is determined. A first average response time, wherein the first average response time is an average of response times of a first set of operations of the device is determined. A second average response time is determined, wherein the second average response time is an average of response times of a second set of operations of the device, wherein each of the second set of operations is initiated under conditions of minimal interference of the device. A threshold based on the estimated level of concurrency is determined. The estimated level of concurrency is updated based, at least in part, on a ratio of the second average response time to the first average response time.

Abstract: Free space collection in a log structured storage system. In response to receiving a request to collect free space, the segment in a recently invalidated segment list having the largest cumulative sum of invalidation duration values is selected for free space collection if this cumulative sum is larger than the cumulative sum of invalidation duration values for the segment in a stable segment list having the largest cumulative sum of invalidation duration values. Otherwise, the segment in the stable segment list having the largest cumulative sum of invalidation duration values is selected for free space collection. emptying. The selected segments are then emptied and become available for the writing of data to their tracks.

Abstract: Method, system, and computer program product embodiments for facilitating deduplication product testing in a computing environment are provided. In one such embodiment, data to be processed through the deduplication product testing is arranged into a single, continuous stream. At least one of a plurality of random modifications are applied to the arranged data in a self-similar pattern exhibiting scale invariance. A plurality of randomly sized subsets of the arranged data modified with the self-similar pattern is mapped into each of a plurality of randomly sized deduplication test files which are calibrated against input/output (I/O) trace data obtained in the computing environment.

Abstract: Free space collection in a log structured storage system. In response to receiving a request to collect free space, the segment in a recently invalidated segment list having the largest cumulative sum of invalidation duration values is selected for free space collection if this cumulative sum is larger than the cumulative sum of invalidation duration values for the segment in a stable segment list having the largest cumulative sum of invalidation duration values. Otherwise, the segment in the stable segment list having the largest cumulative sum of invalidation duration values is selected for free space collection. emptying. The selected segments are then emptied and become available for the writing of data to their tracks.

Abstract: A method, for migrating newly allocated data into a second storage tier, includes receiving a request to store a data item. The method includes allocating an extent to a first storage tier to store the new data item. The method includes determining whether an extent is newly allocated on the first storage tier. The method includes migrating, by avoiding a learning phase, the newly allocated extent to the second storage tier from the first storage tier.

Abstract: Method, system, and computer program product embodiments for facilitating deduplication product testing in a computing environment are provided. In one such embodiment, data to be processed through the deduplication product testing is arranged into a single, continuous stream. At least one of a plurality of random modifications are applied to the arranged data in a self-similar pattern exhibiting scale invariance. A plurality of randomly sized subsets of the arranged data modified with the self-similar pattern is mapped into each of a plurality of randomly sized deduplication test files.

Abstract: A mechanism is provided for optimizing free space collection in a storage system having a plurality of segments. A collection score value is calculated for least one of the plurality of segments. The collection score value is calculated by determining a sum, across tracks in the segment, of the amount of time over a predetermined period of time during which the track has been invalid due to a more recent copy being written in a different segment. Segments are chosen for free space collection based on the determined collection score value.

Abstract: A method, for migrating newly allocated data into a second storage tier, includes receiving a request to store a data item. The method includes allocating an extent to a first storage tier to store the new data item. The method includes determining whether an extent is newly allocated on the first storage tier. The method includes migrating, by avoiding a learning phase, the newly allocated extent to the second storage tier from the first storage tier.

Abstract: A mechanism is provided in a cache subsystem for cache prefetching based on non-sequential access. The mechanism determines frequently accessed non-sequential cache records in the cache subsystem. The mechanism collects trailing record statistics for the frequently accessed non-sequential cache records. The mechanism determines a caching strategy. The caching strategy comprises prefetching a set of trailing records responsive to a read of a given frequently accessed non-sequential cache record. The mechanism applies the caching strategy to the cache subsystem.

Abstract: Monitoring a level of utilization is provided. An initial numerical range based, at least in part, on a count of service channels of a device is determined. A candidate numerical range, defined by an upper value and a lower value, based, at least in part, on the initial numerical range, is determined. A level of utilization of a first measurement interval of the device is estimated by: repeatedly updating the lower value and the upper value based, at least in part, on the level of utilization, until the lower value and the upper value differ less than a pre-determined threshold; and determining an estimated level of utilization based, at least in part, on the lower value and the upper value. The estimated level of utilization is reported.

Abstract: Monitoring a level of utilization is provided. A threshold is determined based, at least in part, on a count of service channels of a device. An upper boundary value of a numerical range is determined based, at least in part, on the count of service channels. A lower boundary value of the numerical range is determined based, at least in part, on the threshold. Whether a count of outstanding requests of the device is contained within the numerical range is determined. An estimated level of utilization of the device is determined based, at least in part, on the upper boundary value, the lower boundary value, the count of service channels, and the count of outstanding requests. The estimated level of utilization is reported.

Abstract: Estimating a level of concurrency is provided. An estimated level of concurrency of a device is determined. A first average response time, wherein the first average response time is an average of response times of a first set of operations of the device is determined. A second average response time is determined, wherein the second average response time is an average of response times of a second set of operations of the device, wherein each of the second set of operations is initiated under conditions of minimal interference of the device. A threshold based on the estimated level of concurrency is determined. The estimated level of concurrency is updated based, at least in part, on a ratio of the second average response time to the first average response time.

Abstract: Various embodiments for managing data by a processor in a multi-tiered computing storage environment. Input/Output (I/O) statistics are examined from each of cache and device drivers in the computing storage environment. Based on the I/O statistics, a ranking mechanism is applied to differentiate data between at least a cache rank and a Solid State Drive (SSD) rank. The ranking mechanism migrates data between the cache rank and SSD rank such that storage space in the cache rank is reserved for those of the plurality of data workload types having a greater adverse effect on a storage performance characteristic if stored in the SSD rank than if those workload types were stored in the cache rank.

Abstract: A method, for migrating newly allocated data into a second storage tier, includes receiving a request to store a data item. The method includes allocating an extent to a first storage tier to store the new data item. The method includes determining whether an extent is newly allocated on the first storage tier. The method includes migrating, by avoiding a learning phase, the newly allocated extent to the second storage tier from the first storage tier.

Abstract: A mechanism is provided in a cache subsystem for cache prefetching based on non-sequential access. The mechanism determines frequently accessed non-sequential cache records in the cache subsystem. The mechanism collects trailing record statistics for the frequently accessed non-sequential cache records. The mechanism determines a caching strategy. The caching strategy comprises prefetching a set of trailing records responsive to a read of a given frequently accessed non-sequential cache record. The mechanism applies the caching strategy to the cache subsystem.

Abstract: A data storage system comprising a Quality of Service server to optimize revenue realized under multiple service level agreements with a data storage client.

Abstract: Monitoring the division of input/output (I/O) loading within a storage system is provided where the storage system includes one or more storage devices and one or more ranks, each rank including a plurality of extents. The I/O loading of individual extents is estimated for each of the one or more ranks of the storage system by determining an average disk utilization in a rank, measuring a total heat for all extents in the rank, and based on the determined average disk utilization in the rank and the measured total heat for all extents in the rank, calculating a contribution of each extent to the utilization of the rank.

Abstract: A mechanism is provided in a cache subsystem for cache prefetching based on non-sequential access. The mechanism determines frequently accessed non-sequential cache records in the cache subsystem. The mechanism collects trailing record statistics for the frequently accessed non-sequential cache records. The mechanism determines a caching strategy. The caching strategy comprises prefetching a set of trailing records responsive to a read of a given frequently accessed non-sequential cache record. The mechanism applies the caching strategy to the cache subsystem.

Abstract: A method for improving I/O performance using queuing latency feedback initially generates, at a host system, I/O for processing on a storage system. The I/O is received at the storage system and queuing latency experienced by the I/O is measured as the I/O is processed by the storage system. The queuing latency is returned to the host system. The host system may use the queuing latency to understand delays and resource contention within the storage system and enable the host system to more effectively take actions that improve I/O performance and compliance with SLAs. A corresponding system and computer program product are also disclosed.

Abstract: A mechanism is provided in a cache subsystem for cache prefetching based on non-sequential access. The mechanism determines frequently accessed non-sequential cache records in the cache subsystem. The mechanism collects trailing record statistics for the frequently accessed non-sequential cache records. The mechanism determines a caching strategy. The caching strategy comprises prefetching a set of trailing records responsive to a read of a given frequently accessed non-sequential cache record. The mechanism applies the caching strategy to the cache subsystem.