Abstract:
A computer-executable method, system, and computer program product of managing a data storage system, wherein the data storage system includes a cache and a data storage array, the computer-executable method, system, and computer program product comprising initializing the cache, wherein the initializing comprises creating a first list related to data stored on the cache, and creating a second list related to data stored on the data storage array, updating the first list based on received I/O requests, updating the second list based on received I/O requests, and managing data on the cache based on the first list and the second list.

Description:
A portion of the disclosure of this patent document may contain command formats and other computer language listings, all of which are subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
     TECHNICAL FIELD 
     This invention relates to data storage. 
     BACKGROUND 
     Computer systems are constantly improving in terms of speed, reliability, and processing capability. As is known in the art, computer systems which process and store large amounts of data typically include a one or more processors in communication with a shared data storage system in which the data is stored. The data storage system may include one or more storage devices, usually of a fairly robust nature and useful for storage spanning various temporal requirements, e.g., disk drives. The one or more processors perform their respective operations using the storage system. Mass storage systems (MSS) typically include an array of a plurality of disks with on-board intelligent and communications electronics and software for making the data on the disks available. 
     Companies that sell data storage systems and the like are very concerned with providing customers with an efficient data storage solution that minimizes cost while meeting customer data storage needs. It would be beneficial for such companies to have a way for reducing the complexity of implementing data storage. 
     SUMMARY 
     A computer-executable method, system, and computer program product of managing a data storage system, wherein the data storage system includes a cache and a data storage array, the computer-executable method, system, and computer program product comprising initializing the cache, wherein the initializing comprises creating a first list related to data stored on the cache, and creating a second list related to data stored on the data storage array, updating the first list based on received I/O requests, updating the second list based on received I/O requests, and managing data on the cache based on the first list and the second list. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Objects, features, and advantages of embodiments disclosed herein may be better understood by referring to the following description in conjunction with the accompanying drawings. The drawings are not meant to limit the scope of the claims included herewith. For clarity, not every element may be labeled in every figure. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments, principles, and concepts. Thus, features and advantages of the present disclosure will become more apparent from the following detailed description of exemplary embodiments thereof taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a simplified illustration of a data storage system, in accordance with an embodiment of the present disclosure; 
         FIG. 2  is an alternate simplified illustration of a data storage system, in accordance with an embodiment of the present disclosure; 
         FIG. 3  is a simplified illustration of caching on a data storage system, in accordance with an embodiment of the present disclosure; 
         FIG. 4  is a simplified illustration of a data storage system managing cache usage, in accordance with an embodiment of the present disclosure; 
         FIG. 5  is a simplified illustration of message processing in a data storage system, in accordance with an embodiment of the present disclosure; 
         FIG. 6  is a simplified illustration of a data storage system managing caching of data storage, in accordance with an embodiment of the present disclosure; 
         FIG. 7  is a simplified flowchart of a method of managing cache in a data storage system, in accordance with an embodiment of the present disclosure; 
         FIG. 8  is an alternative simplified flowchart of a method of managing cache in a data storage system, in accordance with an embodiment of the present disclosure; 
         FIG. 9  is an example of an embodiment of an apparatus that may utilize the techniques described herein, in accordance with an embodiment of the present disclosure; and 
         FIG. 10  is an example of a method embodied on a computer readable storage medium that may utilize the techniques described herein, in accordance with an embodiment of the present disclosure. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     Typically, data storage systems are relied upon to provide high performance solutions. Traditionally, high performance solutions mean that a data storage system is fast, reliable, and efficient in their use of data storage resources. Generally, performance of a data storage system may be affected by where, within the data storage system, data is stored and whether the data storage system is enabled to predict future I/O requests. Conventionally, being able to improve performance of predictive systems within a data storage system may be beneficial to the performance of a data storage system. 
     In many embodiments, the current disclosure may enable increased performance of a data storage system by actively initiating the eviction process of cache areas. In various embodiments the current disclosure may enable monitoring of I/Os received by the data storage system to determine which portions of data storage may be most recently used and/or may be more commonly used by applications using the data storage system. In certain embodiments, the current disclosure may enable a data management module to move data from active areas of a source disk to cache before cache evicts data stored within. In some embodiments, active areas of a source disk may be pre-mapped to portions of cache. 
     In many embodiments, a data management module may be enabled to manage portions of cache related to portions of data stored in a data storage array. In various embodiments, a portion of data may include an extent, Lun, or other contiguous area of a data storage array. In certain embodiments, contiguous areas may be enabled to map to cache which may enable efficient use of cache when accessing a particular set and/or contiguous area. In certain embodiments, a data management module may analyze and/or rank data stored within a data storage system. In other embodiments, ranking may include ordering data within a data storage system by Most Recently Used (MRU), Least Recently Used (LRU), and/or other methods of ordering data. 
     In many embodiments, data storage management module may be enabled to maintain a list and/or queue of data stored within cache. In various embodiments, data storage management module may be enabled to maintain a list and/or queue of data stored within each contiguous area within the data storage system. In some embodiments, a data storage management module may be able to rank data on the data storage system based on a list and/or queue of data stored within cache and contiguous areas within a data storage system. 
     In many embodiments, a data storage management module may periodically refresh each ranked list and/or queue to determine an optimal usage of cache. In various embodiments, an optimal usage of cache may mean removing low ranking cached data from cache and replacing the low ranking cached data with higher ranking data from one or more contiguous areas in the data storage system. In certain embodiments, a data storage management module may be enabled to predict disk access and may be enabled to effectively pre-fetch active areas of data storage into cache. 
     Refer to the example embodiment of  FIG. 1 .  FIG. 1  is a simplified illustration of a data storage system, in accordance with an embodiment of the present disclosure. As shown, Data storage system  100  includes Host  110  which includes data management module  120  and cache  130  and is in communication with data storage array  140 . Application ( 105 A-C,  105  generally) are in communication with data storage system  100  and are utilizing host  110  and data storage array  140  to fulfill data storage needs of application  105 . 
     Refer to the example embodiment of  FIG. 2 .  FIG. 2  is an alternate simplified illustration of a data storage system, in accordance with an embodiment of the present disclosure. As shown, data storage system  200  includes host  210  and data storage array  240 . Host  210  includes cache  230  and data management  220 . In this embodiment, data management module  220  is enabled to manage cached data  235  and data  245  stored on cache  230  and data storage array  240 , respectively. 
     Refer to the example embodiment of  FIG. 3 .  FIG. 3  is a simplified illustration of a data storage system mapping cache to contiguous areas in a data storage array, in accordance with an embodiment of the present disclosure. As shown, data storage system  300  includes Host  310  and data storage array  340 . In this embodiment, Data Storage Array  340  includes contiguous areas ( 342 A-L,  342  generally). As shown, a subset of contiguous areas  342  contain data blocks ( 346 A-H,  346  generally). Each data block  346  is enabled to be mapped to portions ( 332 A-F,  332  generally) of cache  330 . In this embodiment, data block  346 A is mapped to cached block  348 A on portion  332 A. Data block  346 B is mapped to cached block  348 B on portion  332 B. Data block  346 C is mapped to cached block  348 C on portion  332 C. Data block  346 D is mapped to cached block  348 D on portion  332 D. Data block  346 E is mapped to cached block  348 E on portion  332 E. Data block  346 F is mapped to cached block  348 F on portion  332 F. Data blocks  346 G,  346 H are stored on contiguous areas  342 G,  342 H. As shown, data blocks  346 G,  346 H are enabled to be stored on cache  330 , however, data blocks  346 G,  346 H are not currently stored in cache. 
     In this embodiment, data management module  320  is enabled to maintain a cache queue  322  and data storage array queue  324 . Cache queue  322  is a list of data stored within cache  330  ranked by Least Recently Used. Data Storage Array Queue  324  is a list of data stored within data storage array  340  ranked by Least Recently Used. Data management module  320  is enabled to analyze incoming I/O to populate cache Queue  322  and Data storage array queue  324 . Data management module  320  is enabled to utilize cache queue  322  and Data storage array queue  324  to make determinations of whether data blocks stored on data storage array  340  should be cached on cache  330 . Data management module  320  is enabled to actively evict data blocks from cache  330  and cache data blocks from data storage array  340  to cache  330 . In many embodiments, a data management module may be enabled to evict a data block from cache that is the lowest ranked element in a cache queue. In various embodiments, a data management module may be enabled to fill an empty portion of cache with the highest ranked element in the data storage array queue. 
     Refer to the example embodiment of  FIG. 4 .  FIG. 4  is a simplified illustration of internal queues of a data management module, in accordance with an embodiment of the present disclosure. As shown, Cache queue  410  and Data storage array queue  420  each include tables of data block stored within Cache  230  ( FIG. 2 ) and Data Storage Array  240  ( FIG. 2 ) respectively. In this embodiment, cache queue  410  notes that Cache  230  ( FIG. 2 ) is caching data blocks  412 ,  414 ,  416  which are mapped from data blocks  424 ,  426 ,  428 . Data Storage array queue  420  notes that Data Storage Array  240  ( FIG. 2 ) is storing data blocks  422 ,  424 ,  426 ,  428 . Within Cache queue  410 , data blocks  412 ,  414 ,  416  are ordered by Least Recently Used, where data block  412  has been accessed most recently and data block  416  has been accessed least recently. Within Data storage Array Queue  420 , data blocks  422 ,  424 ,  426 ,  428  are ordered by Least Recently Used, where data block  422  has been accessed most recently and data block  428  has been accessed least recently. In many embodiments, a data management module may be enabled to evict a lower ranking data block stored in cache for a higher ranking data block stored on a data storage array. In various embodiments, a cache queue and a data storage array queue may enable a data management module to determine which data blocks may be evicted from cache. In certain embodiments, a cache queue and a data storage array queue may enable a data management module to determine which data blocks from a data storage array may be cached to promote efficient use of the cache. 
     Refer to the example embodiment of  FIG. 5 .  FIG. 5  is a simplified illustration of an application interacting with a data storage system, in accordance with an embodiment of the present disclosure. As shown, data storage system  500  includes host  510  and data storage array  540 . Host  510  includes cache  530  and data management module  520 . Data management module  520  is enabled to maintain a cache queue  522  and a storage array queue  524  to enable the data management module  520  to make determinations on whether to cache data from data storage array  540  and/or evict data from cache  530 . In this embodiment, data management module  520  is enabled to analyze incoming I/Os received in message  507  to determine which portions of cache  530  and which portions of data storage array  540  to manage. 
     Refer to the example embodiment of  FIG. 6 .  FIG. 6  is a simplified illustration of a data management module managing data within a data storage system, in accordance with an embodiment of the present disclosure. As shown, data storage system  600  includes host  610  and data storage array  640 . Host includes data management module  620  and cache  630 . In this embodiment, data management module  620  is enabled to manage cache  630  using message  612 . In many embodiments, the data management module may be enabled to direct a caching module to evict one or more portions of data based on analysis of incoming I/Os. In various embodiments, a data management module&#39;s cache queue and/or data storage array queue may enable the data management module to determine which portions of cache to evict and which portions of the data storage array to cache. As show, cache  630  is enabled to evict portions of data within cache  630 . Cache  630  is enabled to request data from data storage array  640  using message  632 . In this embodiment, Cache  630  is enabled to receive data for caching using message  634 . 
     Refer to the example embodiments of  FIGS. 5 and 7 .  FIG. 7  is a simplified flowchart of a method of managing a data storage system, in accordance with an embodiment of the present disclosure. Initialization of data storage system  500  (Step  700 ) includes dividing data storage array  540  into contiguous areas and/or sets to be managed by data management module  520 . Initialization includes Data management module  520  creating lists cache queue  522  and data storage array queue  524  to maintain records of how cache  530  and data storage array  540  are being used in data storage system  500 . In this embodiment, Application  505  communicates I/O requests to data storage system  500  using message  507 . Data management module  520  receives and analyzes each I/O request to update cache queue  522  and data storage array queue  524  (Step  710 ). Data management module  520  uses cache queue  522  and data storage array queue  524  to manage cache determining whether to move data from data storage array  540  to cache  530  (Step  720 ). 
     Refer to the example embodiments of  FIGS. 6 and 8 .  FIG. 8  is an alternative simplified flowchart of a method of managing data in a data storage system, in accordance with an embodiment of the present disclosure. As shown, data storage system  600  includes host  610  and data storage array  640 . Application  605  is utilizing data storage system  600  to fulfill data storage needs of Application  605 . In this embodiment, data management module  620  maintains cache queue  622  and data storage queue  624  support analysis of I/Os requests received from Application  605 . As shown, cache queue  622  contains references to each portion of data stored within cache  630 . Each stored reference in cache queue  622  is ordered by least recently used allowing data management module to determine which portions of cache  630  to evict. Data storage array queue  624  contains references to each portion of data stored within data storage array  640 . Each stored reference in data storage array queue  624  is ordered by least recently used allowing data management module to determine which portions of data storage array  640  to cache in cache  630 . Upon receiving I/O requests from application  605 , data management module  620  updates cache queue  622  and data storage array queue  624  (Step  800 ). Data management module  620  analyzes cache queue  622  and data storage array queue  624  to determine an efficient allocation of resources (Step  810 ). In this embodiment, Data management module  620  evicts the least recently used portion of Cache  630  and replaces the evicted portion with a portion from data storage array  640  not already stored in cache  630  (Step  820 ). As shown, data management predicts future usage and actively manages cache  630  usage. 
     The methods and apparatus of this invention may take the form, at least partially, of program code (i.e., instructions) embodied in tangible non-transitory media, such as floppy diskettes, CD-ROMs, hard drives, random access or read only-memory, or any other machine-readable storage medium. 
       FIG. 9  is a block diagram illustrating an apparatus, such as a computer  910  in a network  900 , which may utilize the techniques described herein according to an example embodiment of the present invention. The computer  910  may include one or more I/O ports  902 , a processor  903 , and memory  904 , all of which may be connected by an interconnect  925 , such as a bus. Processor  903  may include program logic  905 . The I/O port  902  may provide connectivity to memory media  983 , I/O devices  985 , and drives  987 , such as magnetic or optical drives. When the program code is loaded into memory  704  and executed by the computer  910 , the machine becomes an apparatus for practicing the invention. When implemented on one or more general-purpose processors  903 , the program code combines with such a processor to provide a unique apparatus that operates analogously to specific logic circuits. As such, a general purpose digital machine can be transformed into a special purpose digital machine. 
       FIG. 10  is a block diagram illustrating a method embodied on a computer readable storage medium  1060  that may utilize the techniques described herein according to an example embodiment of the present invention.  FIG. 10  shows Program Logic  1055  embodied on a computer-readable medium  1060  as shown, and wherein the Logic is encoded in computer-executable code configured for carrying out the methods of this invention and thereby forming a Computer Program Product  1000 . Program Logic  1055  may be the same logic  905  on memory  904  loaded on processor  903  in  FIG. 9 . The program logic may be embodied in software modules, as modules, as hardware modules, or on virtual machines. 
     The logic for carrying out the method may be embodied as part of the aforementioned system, which is useful for carrying out a method described with reference to embodiments shown in, for example,  FIGS. 1-10 . For purposes of illustrating the present invention, the invention is described as embodied in a specific configuration and using special logical arrangements, but one skilled in the art will appreciate that the device is not limited to the specific configuration but rather only by the claims included with this specification. 
     Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present implementations are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.