International Business Machines Corporation

Xiao-Yu Hu

Robert Haas

Evangelos Stavros Eleftheriou

Roman Alexander Pletka

Ioannis Koltsidas

Lokesh M Gupta

Michael T Benhase

Stephen LaRoux Blinick

Matthew J Kalos

Ilias Iliadis

Karl Allen Nielsen

Werner K Bux

Nikolas Ioannou

Kevin J Ash

Roy Daron Cideciyan

Ajay Dholakia

Patrick Droz

Christian Cachin

René A Pawlitzek

System and method for operating a solid state memory containing a memory space. The present invention provides a computerized system that includes a solid state memory having a memory space; a controller adapted to use a first portion of the memory space as a cache; and a garbage collector adapted to use a second portion of the memory space to collect garbage in the solid state memory. The controller is adapted to change a size of at least one of the first portion and the second portion of the memory space during operation of the solid state memory.

Cache allocation in a computerized system

The population of data to be admitted into secondary data storage cache of a data storage system is controlled by determining heat metrics of data of the data storage system. If candidate data is submitted for admission into the secondary cache, data is selected to tentatively be evicted from the secondary cache; candidate data provided to the secondary data storage cache is rejected if its heat metric is less than the heat metric of the tentatively evicted data; and candidate data submitted for admission to the secondary data storage cache is admitted if its heat metric is equal to or greater than the heat metric of the tentatively evicted data.

Selective population of secondary cache employing heat metrics

In one embodiment, a method of managing data includes storing a first copy of data in a solid state memory using a controller of the solid state memory, and storing a second copy of the data in a hard disk drive memory using the controller. Write requests are served substantially simultaneously at both the solid state memory and the hard disk drive memory under control of the controller. In another embodiment, a system for storing data includes a solid state memory, at least one hard disk drive memory, and a controller for controlling storage of data in both the solid state memory and the hard disk drive memory. Other methods, systems, and computer program products are also described according to various embodiments.

Reliability scheme using hybrid SSD/HDD replication with log structured management

For efficient track destage in secondary storage in a more effective manner, for temporal bits employed with sequential bits for controlling the timing for destaging the track in a primary storage, if a first bit has at least one of a lower amount of holes and a hotter data heat metric, it is moved to the lower speed cache level. If the first bit has a hotter data heat and greater than a predetermined number of holes, the first bit is discarded.

Promotion of partial data segments in flash cache

For movement of partial data segments within a computing storage environment having lower and higher levels of cache by a processor, a whole data segment containing one of the partial data segments is promoted to both the lower and higher levels of cache, including considering an Input/Output Performance (IOP) metric, a bandwidth metric, and a garbage collection metric, and a whole data segment is promoted containing the one of the partial data segments to both the lower and higher levels of cache.

Management of partial data segments in dual cache systems

An apparatus and method for a memory controller for managing scheduling requests in a solid state memory device. The memory includes a set of units wherein a unit within the set of units is erasable as a whole by a unit reclaiming process resulting in a free unit available for writing data to. The memory controller further includes a first queue for queuing user requests for reading and/or writing data from/to the memory, and a second queue for queuing unit reclaiming requests for executing the unit reclaiming process. A scheduler is provided for selecting user requests from the first queue and unit reclaiming requests from the second queue for execution according to a defined ratio. The defined ratio is a variable ratio, is dependent on the current number of free units, and permits the memory controller to select requests from both the first queue and the second queue.

Scheduling requests in a solid state memory device

For efficient track destage in secondary storage in a more effective manner, for temporal bits employed with sequential bits for controlling the timing for destaging the track in a primary storage, a preference of movement to lower speed cache level is implemented based on at least one of an amount of holes and a data heat metric. If a first bit has at least one of a lower amount of holes and a hotter data heat metric, it is moved to the lower speed cache level ahead of a second bit that has at least one of a higher amount of holes and a cooler data heat. If the first bit has a hotter data heat and greater than a predetermined number of holes, the first bit is discarded.

In one embodiment, a method of managing data includes managing a first copy of data in a solid state memory using a controller of the solid state memory, and managing a second copy of the data in a hard disk drive memory using the controller. In another embodiment, a system for storing data includes a solid state memory, at least one hard disk drive memory, and a controller for controlling storage of data in both the solid state memory and the hard disk drive memory. Other methods, systems, and computer program products are also described according to various embodiments.

Space of a data storage memory of a data storage memory system is reclaimed by determining heat metrics of data stored in the data storage memory; determining relocation metrics related to relocation of the data within the data storage memory; determining utility metrics of the data relating the heat metrics to the relocation metrics for the data; and making the data whose utility metric fails a utility metric threshold, available for space reclamation. Thus, data that otherwise may be evicted or demoted, but that meets or exceeds the utility metric threshold, is exempted from space reclamation and is instead maintained in the data storage memory.

Selective space reclamation of data storage memory employing heat and relocation metrics

A method for managing cache memory in a flash cache architecture. The method includes providing a storage cache controller, at least a flash memory comprising a flash controller, and at least a backend storage device, and maintaining read cache metadata for tracking on the flash memory cached data to be read, and write cache metadata for tracking on the flash memory data expected to be cached.

Management of cache memory in a flash cache architecture

For movement of partial data segments within a computing storage environment having lower and higher levels of cache by a processor, a whole data segment containing one of the partial data segments is promoted to both the lower and higher levels of cache. Requested data of the whole data segment is split and positioned at a Most Recently Used (MRU) portion of a demotion queue of the higher level of cache.

A data storage system including at least one memory device array including memory devices for storing data; and a storage subsystem controller for performing a method for operating the memory devices within the memory device array by relocating parity entities from a first memory device to a spare memory device replacing a failed memory device, and by storing one or more of reconstructed data entities on the first memory device.

Operating a data storage system

The population of data to be inserted into secondary data storage cache is controlled by determining a heat metric of candidate data; adjusting a heat metric threshold; rejecting candidate data provided to the secondary data storage cache whose heat metric is less than the threshold; and admitting candidate data whose heat metric is equal to or greater than the heat metric threshold. The adjustment of the heat metric threshold is determined by comparing a reference metric related to hits of data most recently inserted into the secondary data storage cache, to a reference metric related to hits of data most recently evicted from the secondary data storage cache; if the most recently inserted reference metric is greater than the most recently evicted reference metric, decrementing the threshold; and if the most recently inserted reference metric is less than the most recently evicted reference metric, incrementing the threshold.

Growing community of inventors

Horgen, Switzerland

Xiao-Yu Hu