Patent Publication Number: US-9432300-B2

Title: Allocation of storage resources in a networked computing environment based on energy utilization

Description:
RELATED U.S. APPLICATION DATA 
     The present patent document is a continuation of U.S. patent application Ser. No. 13/073,081, filed Mar. 28, 2011, entitled “ALLOCATION OF STORAGE RESOURCES IN A NETWORKED COMPUTING ENVIRONMENT BASED ON ENERGY UTILIZATION”. The disclosure of U.S. patent application Ser. No. 13/073,081 is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention generally relates to allocation of storage resources based on energy utilization. Specifically, the present invention relates to the provision of storage resources for different workloads in an energy efficient manner in a networked computing environment (e.g., in a cloud computing environment). 
     BACKGROUND 
     The cloud computing environment is an enhancement to the predecessor grid environment, whereby multiple grids and other computation resources may be further abstracted by a cloud layer, thus making disparate devices appear to an end-consumer as a single pool of seamless resources. These resources may include such things as physical or logical computing engines, servers and devices, device memory, and storage devices. 
     Energy consumption is becoming a growing concern for enterprise storage clouds. Specifically, as workloads are added to a storage cloud, the corresponding power/energy consumption goes up, which can drive up operational costs. Different workloads have different characteristics that may be defined in terms of Input/Output (I/O) per second, cache hit rate, read-write ratio, random-sequential ratio, etc. In addition to the type and configuration of underlying storage resources, these workload parameters also influence the amount of energy consumed by the corresponding workloads. Ad-hoc allocation of storage resources may result in inefficient resource utilization as well as higher energy consumption. 
     SUMMARY 
     Embodiments of the present invention provide an approach to provision storage resources (e.g., across an enterprise storage system (ESS) such as a general parallel file system (GPFS) or the like) for different workloads in an energy efficient manner. The system evaluates different energy profiles/workloads&#39; energy consumption characteristics of storage devices to determine an allocation plan that reduces the energy cost (e.g., results in the lowest cost/energy consumption for handling a storage workload). In a typical embodiment, energy consumption characteristics for handling a particular storage workload will be determined. Thereafter, a type of storage device capable of handling the workload will be determined. Then, an allocation plan that results in the most efficient energy consumption for handling the workload will be developed. In general, the allocation plan is based upon the energy consumption characteristics and an energy efficiency algorithm. The energy efficiency algorithm serves to identify storage device(s) that can handle the workload in such a way as to reduce total energy consumption and, accordingly, costs. Along these lines, the energy efficiency algorithm may also consider other factors such as capacity and load of storage devices and service level agreement (SLA) terms in addition to energy costs (e.g., over times of day and/or days of week). In any event, at least one storage device can then be selected for handling the storage workload according to the allocation plan. 
     A first aspect of the present invention provides a method for energy efficient allocation of storage resources in a networked computing environment, comprising: determining energy consumption characteristics of a storage workload in the networked computing environment; selecting a type of storage device for handling the storage workload; developing an allocation plan to result in a most efficient energy consumption for handling the workload, the allocation plan being based upon the energy consumption characteristics, a set of device models for a set of storage devices having the type, and an energy efficiency algorithm; and selecting at least one storage device from the set of storage devices for handling the storage workload according to the allocation plan. 
     A second aspect of the present invention provides a system for energy efficient allocation of storage resources in a networked computing environment, comprising: a bus; a processor coupled to the bus; and a memory medium coupled to the bus, the memory medium comprising instructions to: determine energy consumption characteristics of a storage workload in the networked computing environment; select a type of storage device for handling the storage workload; develop an allocation plan to result in a most efficient energy consumption for handling the workload, the allocation plan being based upon the energy consumption characteristics, a set of device models for a set of storage devices having the type, and an energy efficiency algorithm; and select at least one storage device from the set of storage devices for handling the storage workload according to the allocation plan. 
     A third aspect of the present invention provides a computer program product for energy efficient allocation of storage resources in a networked computing environment, the computer program product comprising: a computer readable storage media, and program instructions stored on the computer readable storage media, to: determine energy consumption characteristics of a storage workload in the networked computing environment; select a type of storage device for handling the storage workload; develop an allocation plan to result in a most efficient energy consumption for handling the workload, the allocation plan being based upon the energy consumption characteristics, a set of device models for a set of storage devices having the type, and an energy efficiency algorithm; and select at least one storage device from the set of storage devices for handling the storage workload according to the allocation plan. 
     A fourth aspect of the present invention provides a method for deploying a system for energy efficient allocation of storage resources in a networked computing environment, comprising: deploying a computer infrastructure being operable to: determine energy consumption characteristics of a storage workload in the networked computing environment; select a type of storage device for handling the storage workload; develop an allocation plan to result in a most efficient energy consumption for handling the workload, the allocation plan being based upon the energy consumption characteristics, a set of device models for a set of storage devices having the type, and an energy efficiency algorithm; and select at least one storage device from the set of storage devices for handling the storage workload according to the allocation plan. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings in which: 
         FIG. 1  depicts a cloud computing node according to an embodiment of the present invention. 
         FIG. 2  depicts a cloud computing environment according to an embodiment of the present invention. 
         FIG. 3  depicts abstraction model layers according to an embodiment of the present invention. 
         FIG. 4  depicts a process flow diagram according to an embodiment of the present invention. 
         FIG. 5  depicts an enterprise storage system (ESS) according to an embodiment of the present invention. 
         FIG. 6  depicts a method flow diagram according to an embodiment of the present invention. 
     
    
    
     The drawings are not necessarily to scale. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. The drawings are intended to depict only typical embodiments of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements. 
     DETAILED DESCRIPTION 
     Illustrative embodiments now will be described more fully herein with reference to the accompanying drawings, in which exemplary embodiments are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of this disclosure to those skilled in the art. In the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, the use of the terms “a”, “an”, etc., do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. It will be further understood that the terms “comprises” and/or “comprising”, or “includes” and/or “including”, when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. 
     Enterprise storage clouds are typically comprised of a large number of interconnected components such as servers, switches, raid arrays, disks, etc. Over a period of time, some of these components may become a performance bottleneck. This may be due to change in workload, system mis-configurations, component failure, etc. A component causing energy inefficiency may deteriorate cloud performance, reduce availability, or result in service level agreement (SLA) violation. These may further lead to loss in revenue, customer dissatisfaction, etc. 
     Embodiments of the present invention provide an approach to provision storage resources (e.g., across an enterprise storage system (ESS) such as a general parallel file system (GPFS) or the like) for different workloads in an energy efficient manner. The system evaluates different energy profiles/workloads&#39; energy consumption characteristics of storage devices to determine an allocation plan that reduces the energy cost (e.g., results in the lowest cost/energy consumption for handling a storage workload). In a typical embodiment, energy consumption characteristics for handling a particular storage workload will be determined. Thereafter, a type of storage device capable of handling the workload will be determined. Then, an allocation plan that results in the most efficient energy consumption for handling the workload will be developed. In general, the allocation plan is based upon the energy consumption characteristics and an energy efficiency algorithm. The energy efficiency algorithm serves to identify storage device(s) that can handle the workload in such a way as to reduce total energy consumption and, accordingly, costs. Along these lines, the energy efficiency algorithm may also consider other factors such as capacity and load of storage devices and service level agreement (SLA) terms in addition to energy costs (e.g., over times of day and/or days of week). In any event, at least one storage device can then be selected for handling the storage workload according to the allocation plan. 
     It is further understood in advance that although this disclosure includes a detailed description of cloud computing, implementation of the teachings recited herein are not limited to a cloud computing environment. Rather, embodiments of the present invention are capable of being implemented in conjunction with any other type of computing environment now known or later developed. 
     Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g. networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal management effort or interaction with a provider of the service. This cloud model may include at least five characteristics, at least three service models, and at least four deployment models. 
     Characteristics are as follows: 
     On-demand self-service: a cloud consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed, automatically without requiring human interaction with the service&#39;s provider. 
     Broad network access: capabilities are available over a network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, laptops, and PDAs). 
     Resource pooling: the provider&#39;s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to demand. There is a sense of location independence in that the consumer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). 
     Rapid elasticity: capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time. 
     Measured service: cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active consumer accounts). Resource usage can be monitored, controlled, and reported providing transparency for both the provider and consumer of the utilized service. 
     Service Models are as follows: 
     Software as a Service (SaaS): the capability provided to the consumer is to use the provider&#39;s applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based email). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited consumer-specific application configuration settings. 
     Platform as a Service (PaaS): the capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including networks, servers, operating systems, or storage, but has control over the deployed applications and possibly application-hosting environment configurations. 
     Infrastructure as a Service (IaaS): the capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls). 
     Deployment Models are as follows: 
     Private cloud: the cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on-premises or off-premises. 
     Community cloud: the cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on-premises or off-premises. 
     Public cloud: the cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services. 
     Hybrid cloud: the cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load-balancing between clouds). 
     A cloud computing environment is service-oriented with a focus on statelessness, low coupling, modularity, and semantic interoperability. At the heart of cloud computing is an infrastructure comprising a network of interconnected nodes. 
     Referring now to  FIG. 1 , a schematic of an example of a cloud computing node is shown. Cloud computing node  10  is only one example of a suitable cloud computing node and is not intended to suggest any limitation as to the scope of use or functionality of embodiments of the invention described herein. Regardless, cloud computing node  10  is capable of being implemented and/or performing any of the functionality set forth hereinabove. 
     In cloud computing node  10 , there is a computer system/server  12 , which is operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of well-known computing systems, environments, and/or configurations that may be suitable for use with computer system/server  12  include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments that include any of the above systems or devices, and the like. 
     Computer system/server  12  may be described in the general context of computer system-executable instructions, such as program modules, being executed by a computer system. Generally, program modules may include routines, programs, objects, components, logic, data structures, and so on that perform particular tasks or implement particular abstract data types. Computer system/server  12  may be practiced in distributed cloud computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed cloud computing environment, program modules may be located in both local and remote computer system storage media including memory storage devices. 
     As shown in  FIG. 1 , computer system/server  12  in cloud computing node  10  is shown in the form of a general-purpose computing device. The components of computer system/server  12  may include, but are not limited to, one or more processors or processing units  16 , a system memory  28 , and a bus  18  that couples various system components including system memory  28  to processor  16 . 
     Bus  18  represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnects (PCI) bus. 
     Computer system/server  12  typically includes a variety of computer system readable media. Such media may be any available media that is accessible by computer system/server  12 , and it includes both volatile and non-volatile media, removable and non-removable media. 
     System memory  28  can include computer system readable media in the form of volatile memory, such as random access memory (RAM)  30  and/or cache memory  32 . Computer system/server  12  may further include other removable/non-removable, volatile/non-volatile computer system storage media. By way of example only, storage system  34  can be provided for reading from and writing to a non-removable, non-volatile magnetic media (not shown and typically called a “hard drive”). Although not shown, a magnetic disk drive for reading from and writing to a removable, non-volatile magnetic disk (e.g., a “floppy disk”), and an optical disk drive for reading from or writing to a removable, non-volatile optical disk such as a CD-ROM, DVD-ROM, or other optical media can be provided. In such instances, each can be connected to bus  18  by one or more data media interfaces. As will be further depicted and described below, memory  28  may include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions of embodiments of the invention. 
     The embodiments of the invention may be implemented as a computer readable signal medium, which may include a propagated data signal with computer readable program code embodied therein (e.g., in baseband or as part of a carrier wave). Such a propagated signal may take any of a variety of forms including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. 
     Program code embodied on a computer readable medium may be transmitted using any appropriate medium including, but not limited to, wireless, wireline, optical fiber cable, radio-frequency (RF), etc., or any suitable combination of the foregoing. 
     Program/utility  40 , having a set (at least one) of program modules  42 , may be stored in memory  28  by way of example, and not limitation, as well as an operating system, one or more application programs, other program modules, and program data. Each of the operating system, one or more application programs, other program modules, and program data or some combination thereof, may include an implementation of a networking environment. Program modules  42  generally carry out the functions and/or methodologies of embodiments of the invention as described herein. 
     Computer system/server  12  may also communicate with one or more external devices  14  such as a keyboard, a pointing device, a display  24 , etc.; one or more devices that enable a consumer to interact with computer system/server  12 ; and/or any devices (e.g., network card, modem, etc.) that enable computer system/server  12  to communicate with one or more other computing devices. Such communication can occur via I/O interfaces  22 . Still yet, computer system/server  12  can communicate with one or more networks such as a local area network (LAN), a general wide area network (WAN), and/or a public network (e.g., the Internet) via network adapter  20 . As depicted, network adapter  20  communicates with the other components of computer system/server  12  via bus  18 . It should be understood that although not shown, other hardware and/or software components could be used in conjunction with computer system/server  12 . Examples include, but are not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc. 
     Referring now to  FIG. 2 , illustrative cloud computing environment  50  is depicted. As shown, cloud computing environment  50  comprises one or more cloud computing nodes  10  with which local computing devices used by cloud consumers, such as, for example, personal digital assistant (PDA) or cellular telephone  54 A, desktop computer  54 B, laptop computer  54 C, and/or automobile computer system  54 N may communicate. Nodes  10  may communicate with one another. They may be grouped (not shown) physically or virtually, in one or more networks, such as private, community, public, or hybrid clouds as described hereinabove, or a combination thereof. This allows cloud computing environment  50  to offer infrastructure, platforms, and/or software as services for which a cloud consumer does not need to maintain resources on a local computing device. It is understood that the types of computing devices  54 A-N shown in  FIG. 2  are intended to be illustrative only and that computing nodes  10  and cloud computing environment  50  can communicate with any type of computerized device over any type of network and/or network addressable connection (e.g., using a web browser). 
     Referring now to  FIG. 3 , a set of functional abstraction layers provided by cloud computing environment  50  ( FIG. 2 ) is shown. It should be understood in advance that the components, layers, and functions shown in  FIG. 3  are intended to be illustrative only, and embodiments of the invention are not limited thereto. As depicted, the following layers and corresponding functions are provided: 
     Hardware and software layer  60  includes hardware and software components. Examples of hardware components include mainframes. In one example, IBM® zSeries® systems and RISC (Reduced Instruction Set Computer) architecture based servers. In one example, IBM pSeries® systems, IBM xSeries® systems, IBM BladeCenter® systems, storage devices, networks, and networking components. Examples of software components include network application server software. In one example, IBM WebSphere® application server software and database software. In one example, IBM DB2® database software. (IBM, zSeries, pSeries, xSeries, BladeCenter, WebSphere, and DB2 are trademarks of International Business Machines Corporation registered in many jurisdictions worldwide.) 
     Virtualization layer  62  provides an abstraction layer from which the following examples of virtual entities may be provided: virtual servers; virtual storage; virtual networks, including virtual private networks; virtual applications and operating systems; and virtual clients. 
     In one example, management layer  64  may provide the functions described below. Resource provisioning provides dynamic procurement of computing resources and other resources that are utilized to perform tasks within the cloud computing environment. Metering and pricing provide cost tracking as resources are utilized within the cloud computing environment, and billing or invoicing for consumption of these resources. In one example, these resources may comprise application software licenses. Security provides identity verification for cloud consumers and tasks, as well as protection for data and other resources. Consumer portal provides access to the cloud computing environment for consumers and system administrators. Service level management provides cloud computing resource allocation and management such that required service levels are met. Service Level Agreement (SLA) planning and fulfillment provides pre-arrangement for, and procurement of, cloud computing resources for which a future requirement is anticipated in accordance with an SLA. 
     Workloads layer  66  provides examples of functionality for which the cloud computing environment may be utilized. Examples of workloads and functions which may be provided from this layer include: mapping and navigation; software development and lifecycle management; virtual classroom education delivery; data analytics processing; transaction processing; and storage resource allocation. As mentioned above, all of the foregoing examples described with respect to  FIG. 3  are illustrative only, and the invention is not limited to these examples. 
     It is understood all that functions of the present invention as described herein typically may be performed by the storage resource allocation functionality, which can be tangibly embodied as modules of program code  42  of program/utility  40  ( FIG. 1 ). However, this need not be the case. Rather, the functionality recited herein could be carried out/implemented and/or enabled by any of the layers  60 - 66  shown in  FIG. 3 . 
     It is reiterated that although this disclosure includes a detailed description on cloud computing, implementation of the teachings recited herein are not limited to a cloud computing environment. Rather, the embodiments of the present invention are intended to be implemented with any type of networked computing environment now known or later developed. 
     In general, enterprise datacenters are facing serious challenges to cope with the exponential growth of storage and computing needs. These challenges include cost, performance, and resiliency, among other things. Architectures such as cloud computing environments are being proposed, which address some of the challenges (e.g., management issues). However, some of the issues still remain. One of those challenges is the increase in energy consumption requirements. System administrators not only have to manage performance, resiliency, and other workload requirements, but also the needs of energy-consuming servers, storage, and networking equipments. As more workloads are consolidated in large cloud computing environments, the need for additional energy is also growing. These consolidated environments should be designed to accommodate peak energy and cooling requirements. Failure to do so may result in system failure and/or application downtime, both of which may cause data and revenue loss, missed opportunities, and loss of goodwill. Energy consumed by a particular application and workload depends not only on their I/O and computational characteristics, but also on the type and configuration of the resources they use. Arbitrary allocation and configuration of cloud resources may result in higher energy consumption and may exceed the total energy budget allocated for a particular cloud installation. 
     Storage cloud services can be built on top of shared networked infrastructure(s) with the ability to scale to vast quantities of storage and an astronomical number of I/O transactions per second with low cost and high reliability. These storage services are typically made available in the form of web services API(s) or traditional file system-based interfaces. As indicated, embodiments of the present invention provide an approach for allocating storage (e.g., handling a storage workload) in an enterprise storage system (ESS) such as a general parallel file system (GPFS). It is understood that although a GPFS is used herein as an example, the same concepts could be applied to any type of ESS. 
     In general, a GPFS is based on a shared disk architecture, where the file system data is striped across multiple storage units called network shared disks (NSDs). These NSDs are typically created out of storage logical units (LUNs) that may physically reside in one or more storage subsystem(s). Storage LUNs are typically created out of redundant arrays of independent disks (e.g., a RAID-based storage pool having multiple storage disks). Data stored in a LUN is potentially spread across several disks in the storage pool. This sharing and distribution can be beneficial for performance and fault tolerance, but it can have a negative impact on the energy consumption of the workloads. This is because the distribution of a file system workload across multiple NSDs/LUNs causes all the disks that constitute those LUNs to remain in an active state (e.g., “spinning”). Also, different types of disks (e.g., serial-attached small computer system interface (SAS), serial advanced technology attachment (SATA), solid state drives (SSDs), etc.) consume different amounts of energy and have different performance and reliability characteristics. The approach recited herein provides automated selection of NSDs/LUNs for a given file system workload while optimizing energy and other workload requirements. 
     Referring now to  FIG. 4 , a process flow diagram according to the an embodiment present invention is shown. As depicted, in steps P 1  and P 2 , a storage configuration is determined/discovered. Specifically, storage resources/components/devices of an ESS (e.g., GPFS  70  of  FIG. 5 ), their configurations and interrelationships are determined. Briefly referring to  FIG. 5 , such resources/components/devices can include RAID pools  80 A-N that can be coupled to LUNs  78 A-N. As further shown, LUNs  78 A-N can be coupled to NSDs  76 A-N of clusters  74 A-N (e.g., GPFS clusters). In any event, referring back to  FIG. 4 , the configuration information is fed to workload optimizer (e.g., which can be embodied as program/utility  40  of  FIG. 1 , and which enables storage resource allocation functionality in workloads layer  66  of  FIG. 3 ) in step P 5 . Also received by workload optimizer P 5  are workload characteristics/information (e.g., energy consumption characteristics involved with handling/servicing a given storage workload) in step P 3 , and device models in step P 4 . The device models indicate an energy consumption rate/information about the resources/components/devices in the discovered ESS. Such information can also include a current load on each component/resource, a capacity of each component/resource, and a rate at which each resource/component/device consumes energy under a given load and/or available capacity. 
     Based on the received information (e.g., storage configuration, workload characteristics, device models, etc.), the workload optimizer will apply an energy efficiency algorithm to develop an allocation plan P 6  for handling the storage workload. Along these lines, the allocation plan includes instructions for allocating the storage workload so that the level of energy needed to handle the storage workload can be provided so as to result in the most efficient energy consumption/cost. For example, the allocation plan can call for using a set (at least one) of storage devices of a certain type in a certain manner (e.g., in a certain order, to a certain load, etc.). The energy efficiency algorithm is typically based on the capacity of a set of storage devices, a load on each of the set of storage devices, and an energy consumption of the set of storage devices as derived from the set of device models. As such the workload optimizer could, in a typical embodiment, determine what type of storage device(s) should be used to handle the workload, and then determine what specific instances of devices having those type(s) should be used to accommodate the workload. The allocation plan would further be generated to utilize these devices in the most energy efficient manner. As such, the workload optimizer will balance multiple factors such as handling the storage workload and doing so in a way that results in the most efficient energy consumption/cost (e.g., while still honoring any other factors such as service level agreement (SLA) terms or the like). In any event, in step P 7 , the allocation plan will be deployed and the storage workload handled accordingly. 
     As indicated above, the workload optimizer can select a type of storage device to handle a given storage workload. The selection of the device type can be primarily governed by workload performance and resiliency requirements. For “mission critical” data with high performance and reliability requirements, SAS is the preferred disk type, SSD is recommended for workloads with high random I/O, SATA is preferred for redundant data like logs, etc. The system of the embodiments of the present invention uses these policies and best practices to choose between different disk types. 
     Once the device type is selected, the energy efficiency algorithm will be used to select the actual NSDs for file system creation. Since more disk activities result in higher energy consumption, the algorithm can select NSDs such that total activity (or entropy) of the underlying disks that form the NSDs is minimized. Furthermore, the algorithm can minimize server-level energy consumption by consolidating workloads on fewer storage nodes. 
     In general, the energy efficiency algorithm can be developed as follows:
     Let l Ni   z  denotes the existing load on NSD (or LUN) N i .   Let l Dj   s  denotes the existing load on physical disk D i .   Let C D   r  be the total number of existing active disks   Therefore, total existing load on the disks:   

     
       
         
           
             
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         Similarly, for provisioning the new workload ‘n’, 
         Let l Ni   n  denotes the new load on NSD (or LUN) N i . 
         Let denotes the new load on physical disk 
         Let C D   n  be the total number of active disks after adding the new workload 
         Therefore, total load on the disks after adding the new workload is: 
       
    
     
       
         
           
             
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         For minimizing energy consumption, the optimization algorithm selects NSDs and storage servers such that the following constraints are satisfied: 
         l Dj   z +l dj   n &lt;C nj(i) , where C nj  is the performance capacity of disk D i . 
         (ii) Minimize L D , i.e. Minimize 
       
    
     
       
         
           
             
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         (iii) Minimize C D   n    
         (iv) Minimize active storage server set. 
       
    
     An example of the application of the teachings recited herein is shown in  FIG. 5 . As indicated above,  FIG. 5  depicts a GPFS  70  comprising clusters  76 A-N of NSDs  76 A-N, LUNs  78 A-N, and RAID pools  80 A-N. IN general, clusters  76 A-N can receive workloads (e.g., storage workloads) from one or more clients  72 A-N. Cluster  76 B shows when a storage workload is subject to random allocation among devices. As shown, two different RAID pools  94 A-B are utilized, each of which are coupled to a separate LUN  92 A-B. As such, two non-adjacent NSDs  90 A-B were selected. In contrast, cluster  76 N shows selection in accordance with the embodiments of the present invention (e.g., via the energy efficiency algorithm). As shown, one RAID pool  94 C is coupled to adjacent LUNS  92 C-D, which results in usage of two adjacent NSDs  90 C-D. 
     From  FIG. 5 , it can be seen that if a file system uses two NSDs  90 A-B (or LUNs  92 A-B) from two different RAID pools  94 A-B, it creates activities in more disks. Selecting LUNs  92 C-D from the same RAID pools  94 C makes the other RAID pool idle and allows the storage system to switch the latter to low energy state. In a scenario where the first RAID pool does not have sufficient performance capacity available, then a LUN from another RAID pool can be chosen. 
     Referring now to  FIG. 6 , a method flow diagram according to an embodiment of the present invention is shown. As depicted, in step S 1 , energy consumption characteristics of a storage workload are determined. In step S 2 , a type of storage device for handling the storage workload is selected. In step S 3 , an allocation plan is developed to result in the most efficient energy consumption for handling the workload. As mentioned above, the allocation plan is typically based upon the energy consumption characteristics, a set of device models for a set of storage devices having the particular type selected, and an energy efficiency algorithm. In step S 4 , at least one storage device is selected from the set of storage devices for handling the storage workload according to the allocation plan. 
     While shown and described herein as a storage resource allocation solution, it is understood that the invention further provides various alternative embodiments. For example, in one embodiment, the invention provides a computer-readable/useable medium that includes computer program code to enable a computer infrastructure to provide storage resource allocation functionality as discussed herein. To this extent, the computer-readable/useable medium includes program code that implements each of the various processes of the invention. It is understood that the terms computer-readable medium or computer-useable medium comprise one or more of any type of physical embodiment of the program code. In particular, the computer-readable/useable medium can comprise program code embodied on one or more portable storage articles of manufacture (e.g., a compact disc, a magnetic disk, a tape, etc.), on one or more data storage portions of a computing device, such as memory  28  ( FIG. 1 ) and/or storage system  34  ( FIG. 1 ) (e.g., a fixed disk, a read-only memory, a random access memory, a cache memory, etc.). 
     In another embodiment, the invention provides a method that performs the process of the invention on a subscription, advertising, and/or fee basis. That is, a service provider, such as a Solution Integrator, could offer to provide storage resource allocation functionality. In this case, the service provider can create, maintain, support, etc., a computer infrastructure, such as computer system  12  ( FIG. 1 ) that performs the processes of the invention for one or more consumers. In return, the service provider can receive payment from the consumer(s) under a subscription and/or fee agreement and/or the service provider can receive payment from the sale of advertising content to one or more third parties. 
     In still another embodiment, the invention provides a computer-implemented method for storage resource allocation. In this case, a computer infrastructure, such as computer system  12  ( FIG. 1 ), can be provided and one or more systems for performing the processes of the invention can be obtained (e.g., created, purchased, used, modified, etc.) and deployed to the computer infrastructure. To this extent, the deployment of a system can comprise one or more of: (1) installing program code on a computing device, such as computer system  12  ( FIG. 1 ), from a computer-readable medium; (2) adding one or more computing devices to the computer infrastructure; and (3) incorporating and/or modifying one or more existing systems of the computer infrastructure to enable the computer infrastructure to perform the processes of the invention. 
     As used herein, it is understood that the terms “program code” and “computer program code” are synonymous and mean any expression, in any language, code, or notation, of a set of instructions intended to cause a computing device having an information processing capability to perform a particular function either directly or after either or both of the following: (a) conversion to another language, code, or notation; and/or (b) reproduction in a different material form. To this extent, program code can be embodied as one or more of: an application/software program, component software/a library of functions, an operating system, a basic device system/driver for a particular computing device, and the like. 
     A data processing system suitable for storing and/or executing program code can be provided hereunder and can include at least one processor communicatively coupled, directly or indirectly, to memory elements through a system bus. The memory elements can include, but are not limited to, local memory employed during actual execution of the program code, bulk storage, and cache memories that provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution. Input/output and/or other external devices (including, but not limited to, keyboards, displays, pointing devices, etc.) can be coupled to the system either directly or through intervening device controllers. 
     Network adapters also may be coupled to the system to enable the data processing system to become coupled to other data processing systems, remote printers, storage devices, and/or the like, through any combination of intervening private or public networks. Illustrative network adapters include, but are not limited to, modems, cable modems, and Ethernet cards. 
     The foregoing description of various aspects of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed and, obviously, many modifications and variations are possible. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of the invention as defined by the accompanying claims.