Storing data in multi-region storage devices

An apparatus comprises a storage controller coupled to at least one multi-region storage device. The at least one multi-region storage device comprises two or more storage regions, the two or more storage regions comprising a first storage region associated with a first set of failure characteristics and at least a second storage region associated with a second set of failure characteristics different than the first set of failure characteristics. The storage controller is configured to replicate in the second storage region at least a portion of data that is stored in the first storage region.

BACKGROUND

The present invention relates to storage, and more specifically, to techniques for storing data. Storage devices, such as hard disk drives, continue to grow in storage capacity. In some cases, storage devices have significant capacity that goes unused. Such unused capacity, or empty disk space, typically serves no useful purpose in a computing system other than being available for future data storage.

SUMMARY

Embodiments of the invention provide techniques for storing data in a multi-region storage device.

For example, in one embodiment, an apparatus comprises a storage controller coupled to at least one multi-region storage device. The at least one multi-region storage device comprises two or more storage regions, the two or more storage regions comprising a first storage region associated with a first set of failure characteristics and at least a second storage region associated with a second set of failure characteristics different than the first set of failure characteristics. The storage controller is configured to replicate in the second storage region at least a portion of data that is stored in the first storage region.

DETAILED DESCRIPTION

Illustrative embodiments of the invention may be described herein in the context of illustrative methods, systems and devices for storing data in multi-region storage devices. However, it is to be understood that embodiments of the invention are not limited to the illustrative methods, systems and devices but instead are more broadly applicable to other suitable methods, systems and devices.

As discussed above, storage devices continue to grow in capacity such that in many cases, hard drives and other storage devices have significant unused storage capacity or empty disk space. For a typical user of a computing system including one or more storage devices, the storage devices are underutilized and recording heads, for example, spend significant time flying over blank media. This blank media serves no useful purpose other than its availability for future data storage.

A storage device, for example, may be a mechanical spinning disk drive (e.g., a hard disk drive (HDD)), a solid state drive (SSD), or a hybrid drive that combines HDD and SSD technology. A hybrid drive may be implemented in various ways. Generally, a hybrid drive combines the speed benefits of SSDs with the cost-effective storage capacity of HDDs. The SSD in a hybrid drive typically acts as a cache for data stored on the HDD, improving overall performance by keeping copies of most frequently used data on the SSD.

Hybrid drives may be implemented in various manners, including dual-drive hybrid systems and solid-state hybrid drives. In a dual-drive hybrid system, separate SSD and HDD devices are installed in a same computer, where data placement optimization is performed manually by an end user or automatically through the creation of a hybrid logical device. In solid-state hybrid drives, SSD and HDD functionalities are built into the same physical storage device by adding NAND flash memory to a HDD, where data placement decisions are performed by the device itself in a self-optimized mode or through placement hints supplied by an operating system in a host-hinted mode.

In some embodiments, blank media is used by a computing system to duplicate or mirror data written to a storage device. As an example, data that is recorded on a first surface of a disk platter in a HDD may be mirrored or duplicated on an unused second surface of the disk platter or on another disk platter. In this way, several copies of the user's data can be written to the disk providing increased robustness under a number of different system and device failure scenarios.

For example, in the case of a recording read and/or write head transducer failure, the data normally accessed using the failed recording head may be accessed on another surface of a HDD or other storage device that is accessed using a different recording head. As another example, data can be kept on opposing surfaces of a recording medium, such that a shock, due to dropping the device for instance, is less likely to damage both surfaces on which the data is stored. As a further example, if head disk interactions are detected on one recording head of a disk drive or other storage devices having multiple recording heads, the computing system can automatically switch to an alternative surface or region and recover the data. A user may be notified of the failure condition and given time to recover critical files. As another example, if bearing failures result in surface dependent track misregistration, the computing system can move to a best mechanical surface.

Various types of disk drives have built-in functionality for monitoring their operation, referred to as Self-Monitoring, Analysis and Reporting Technology (S.M.A.R.T.). Several examples of parameters in S.M.A.R.T. may indicate failure or pending failure of components which may lead to read or write errors. Such parameters differ based on the type of storage device.

In mechanical disk drives or HDDs, the following are examples of S.M.A.R.T. parameters indicating failure or pending failure of some portion of a HDD: ID 189 “High Fly Height” is a parameter that detects when a recording head is flying outside its normal operating range, which can indicate a defective air bearing surface of a recording head which can lead to write failures; ID 185 “Head Stability” is a parameter that detects when a recording head read signal is no longer stable, which can lead to read errors; ID 08 “Seek Time Performance” is a parameter that detects mechanical problems in the drive and may be recording head dependent, in a dual actuator arrangement this parameter may indicate failure of one of the recording head actuators; and ID 01 “Read Error Rate” is a parameter that detects when an individual recording head is experiencing errors while reading data.

SSDs may experience failures in particular memory cells. The following are examples of S.M.A.R.T. parameters indicating failure or pending failure of some portion of a SSD: ID 171 “SSD Program Fail Count” is an attribute that returns the total number of flash program operation failures since the drive was deployed; ID 172 “SSD Erase Fail Count” is an attribute that returns the total number of flash erase operation failures since the drive was deployed; and ID 173 “SSD Wear Leveling Count” is a parameter that counts the maximum worst erase count on any block.

It is to be appreciated that the specific S.M.A.R.T. parameters discussed above are presented by way of example only. Various other types of S.M.A.R.T. parameters may be utilized for detecting failure or potential failure of a storage device. In addition, various other types of failure conditions are possible and embodiments are not limited to the specific examples presented above.

While embodiments do not necessarily protect against all possible failure conditions for a storage device, the techniques described herein may be utilized to improve overall robustness of a storage or other computing system and can eliminate at least some failures. Further, embodiments can provide such improved overall robustness without adding any cost to the storage or other computing system.

Storage device reliability is an ongoing problem. Various techniques, such as vibration robustness and ruggedization, are utilized to increase the reliability of storage devices such as HDDs. The techniques described herein can be used to further increase the reliability of storage devices.

For some storage devices, such as disk drives, the granularity with respect to failure is smaller than the entire disk drive itself. Various current systems however, consider the granularity of a storage device at the disk drive level. In embodiments of the invention, a disk drive or other storage device is divided into multiple regions, forming what is referred to herein as a multi-region storage device (MRD). The regions of an MRD may be organized based on physical layout considerations, where the goal is to have an MRD wherein at least two of the regions are associated with different failure characteristics. Thus, disk accesses to a first region of an MRD may fail while access to a second region of the MRD can proceed without any problems.

Regions of an MRD with access failures may be referred to as failed regions. The failed regions may be discovered by a storage controller coupled to the MRD, or may be reported to the storage controller by the MRD itself, such as through a S.M.A.R.T. disk drive monitoring system. A computing system may use one or multiple MRDs for increasing system robustness.

FIG. 1shows a computing system100including a set of MRDs102-1,102-2, . . .102-M, collectively referred to herein as MRDs102, coupled to a storage controller104and a processing device106. The MRD102-1, as shown inFIG. 1includes multiple regions120-1,120-2, . . .120-N, collectively referred to herein as storage regions120. Each of the storage regions120may be associated with different sets of failure characteristics as will be discussed in further detail below. Although not explicitly shown inFIG. 1, other ones of the MRDs102may also comprise multiple storage regions associated with different sets of failure characteristics.

Storage controller104may be a disk controller providing an interface between the MRD102and the rest of computer system100, including the processing device106. The storage controller104, in some embodiments, may further or alternatively be a disk array controller such as a Redundant Array of Independent Disks (RAID) controller. WhileFIG. 1shows all of the MRDs102coupled to the same storage controller104, in other embodiments different ones of the MRDs102may be coupled to different storage controllers and/or processing devices. In addition, in other embodiments a computing system may include only a single MRD such as MRD102-1rather than a set of two or more MRDs.

As discussed above, an MRD such as MRD102-1can be used to provide a higher level of protection against loss of data relative to a storage device not configured as an MRD. In some embodiments, the storage regions120of MRD102-1, for example, may be divided into two or more different groups of storage regions. The division of the storage regions120into the two or more groups may be done such that certain partial disk failures like a malfunctioning recording head or disk surface affects only one group (or more generally less than all groups) of the storage regions120.

A RAID-like implementation may be used on MRD102-1alone, where the different groups of storage regions120make up the storage volumes or logical units (LUNs) for the RAID array. Various types of RAID implementations may be utilized, including RAID1, RAID5, etc. In a system where the MRD102-1implements a RAID1-like implementation using two groups of the storage regions120, any write to the MRD102-1results in two writes, one to each of the two groups of storage regions120. The RAID arrangement may be implemented by the MRD102-1itself, or by software or hardware in the storage controller104and/or processing device106.

Implementing a RAID-like implementation utilizing only a single MRD such as MRD102-1provides various benefits. For example, in a computing system having only a single disk drive, as is common in certain types of computing systems such as laptops and certain desktops, data can still be recovered when the MRD102-1partially fails. Many types of disk failures, such as recording head or disk head failures, can result in loss of access to parts of the disk while other parts of the disk can still be accessed normally. With the increasing size of individual disk drives, duplicating data on the disk is a reasonable approach considering the potential benefits. In a RAID1-like implementation, the MRD102-1's useful size is reduced in half In other arrangements, however, the useful size of the MRD102-1need not be reduced by half. An example of such an arrangement is a RAID5-like implementation, which may reduce the useful size of the MRD102-1by as little as ⅓.

In other embodiments, the MRDs102such as MRD102-1need not utilize a RAID-like implementation. As one example, empty or unused storage space on MRD102-1may be utilized for copying portions of the data stored on the MRD102-1. The mirroring or replication of data between respective ones of the storage regions120may be similarly chosen such that under a variety of partial disk failures data can still be recovered. Mirroring of data, and accessing mirror copies on partial disk failure, may be performed by the storage controller104or the processing device106, possibly utilizing a block storage access hierarchy. Unused disk area can be used to provide higher robustness whenever possible.

Of course, in some arrangements the unused disk area may not be large enough to mirror all data stored on the MRD102-1. In such cases, various algorithms may be used to prioritize which data is mirrored. In one algorithm, different types of data may be assigned different mirroring priorities. Consider, as an example, an arrangement wherein the MRD102-1is the primary hard drive for a user's laptop computer. Certain types of data, such as the user's documents, pictures, videos, etc. may be assigned a higher priority relative to application installation files or base operating system files as the application installation and operating system files may be recovered relatively easily by reinstalling the operating system or application while personal documents, pictures, videos, etc. may be difficult or impossible to replace.

In another algorithm, different ones of the storage regions120may be assigned different priorities based on their likelihood of failure. For example, storage region120-1may be determined to be twice as likely to fail as storage region120-2. Thus, storage region120-1may be assigned a higher priority for mirroring relative to storage region120-2.

In some embodiments, the data error rate for different types of stored data may be subject to differing requirements. As an example, a commercial movie video file may not require the same error rate as a personal video file or bank statement. Thus, in certain algorithms the type of data and error rate requirements may determine which data to mirror or replicate in a MRD. Various other algorithms may be used, including combinations of the above-described algorithms.

In some embodiments, two or more of the MRDs102may be used in a RAID-like arrangement. The storage controller104or processing device106, acting as a RAID controller, may be suitably modified so as to use individual storage regions (or groups of storage regions) on two or more of the MRDs102as storage volumes or LUNs for a RAID array. As one example, the same number and same sized storage regions may be used from each of the MRDs102. Consider an arrangement utilizing two MRDs, MRD102-1and MRD102-1, having the same number of storage regions of the same sizes. For a RAID1 arrangement, normally each of MRD102-1and MRD102-2may be considered as a single storage volume or LUN in the RAID1 setup. In an embodiment, however, the storage regions of each of MRD102-1and MRD102-2may be divided into two groups. Then, a first group of storage regions from MRD102-1and a first group of storage regions from MRD102-2may collectively form a first storage volume or LUN for the RAID1-like arrangement, while a second group of storage regions from the MRD102-1and a second group of storage regions from MRD102-2may collectively form a second storage volume of LUN for the RAID1-like arrangement. For other types of RAID arrangements, including a RAID1-like arrangement utilizing storage regions from more than two of the MRDs102, other arrangements of groups of storage regions may be used.

When a failed storage region is detected in a multiple MRD arrangement, the content of the failed storage region may be reconstructed in a newly added storage region if a suitable such storage region is available. For example, a RAID arrangement utilizing multiple MRDs need not initially utilize all the storage regions of all the MRDs. Instead, one or more storage regions on one or more of the MRDs may be saved for recovery of failed storage regions. Depending on the availability of free storage regions and the reliability requirements of a particular multiple MRD arrangement, the new storage region can be another storage region of a partially failed disk drive, a storage region on another MRD, or a storage region on a spare disk drive.

When a failure is detected in one of the storage regions, the storage controller104and/or processing device106may reconstruct sectors from the failed storage region first. Once the reconstruction is completed, heuristics may be utilized to mirror or replicate sectors from other storage regions that have not yet failed but which are determined as more probable to fail based on the heuristics.

The use of multiple MRDs for a RAID-like arrangement provides various benefits including reduced time of recovery and the recovery of the most vulnerable portions of disk drives first which can become more important as disk drive capacity grows. In RAID arrays, pre-failure replacement occurs when the array senses a future storage device failure and initiates a replacement. Post-failure replacement takes place after a storage device fails. The data on the failed storage device must be rebuilt from the parity data, which can take a considerable amount of time and impacts the availability of data stored on the RAID array. Thus, replicating data in MRDs can provide a path to pre-failure replacement greatly improving RAID availability.

The use of multiple MRDs can also lead to better utilization of disk drives. In addition, RAID arrays can be made from a larger variety of and numbers of disks as a single MRD need not be dedicated to only one RAID array. For example, the storage regions of a single MRD such as MRD102-1may be used in two different RAID-like arrays. Some of the storage regions120of MRD102-1may be used as part of a storage volume for a RAID1 array, while other ones of the storage regions120of MRD102-1may be used as part of a second storage volume for a RAID5 array. Various other arrangements are possible, including arrangements in which individual storage regions of a single MRD such as MRD102-1are used for two different RAID arrays of the same type, such as two different RAID or RAID5 arrays.

While various embodiments described above may be considered proactive, in that mirroring of data is performed prior to detecting failure in any storage region, embodiments are not limited to proactive mirroring. In other embodiments, mirroring may not be performed proactively but may instead be responsive to detecting failure in one or more storage regions of an MRD or responsive to predicting failure in one or more storage regions of an MRD. When a faulty storage region is detected, corrective actions may be taken. This may be done in hardware, such as storage controller104acting as a RAID controller, or in software such as a disk driver of the MRD102or in software implemented using one of or both of storage controller104and processing device106.

Depending on the type of failure, or the prediction of failure, a decision is made as to whether there are other storage regions of a storage or other computing system that have higher probabilities of failure. In such cases, the content of those identified regions are copied into available storage regions with the lowest probability for suffering from the same type of failure.

For example, if a given storage region on a surface of a disk is identified as failed or predicted to fail, other storage regions containing neighboring surfaces may be marked as storage regions with a high probability of failure and the data on such storage regions may be moved, or mirrored, to another storage region or regions which use surfaces far from the failing surface. In some embodiments, this may be done by ranking all storage regions based on the detected failure and sorting the storage regions based on the ranking. A first available storage region with the lowest probability is selected as the destination storage region for moving data.

In some embodiments, there may exist two or more copies of a data segment. In cases where parts of data in a failed storage region are already available in one or more relatively safer storage regions, only those segments of the vulnerable storage region which are not already duplicated on a safer storage region need to be copied. The copy operations may be coordinated by the storage controller104, a driver of the MRD itself, or in software at a higher level such as software implemented by processing device106.

Once the vulnerable data is moved, the process of reconstructing the faulty region may begin. First, the MRD may be scanned to determine whether any portion or portions of the data in the faulty storage region are duplicated in other storage regions. In some embodiments, this may involve keeping a drive directory of where duplicated data is written. In such embodiments, scanning the drive may be replaced by simply table lookups in the drive directory which may be much faster than a scan of the MRD.

If any such portions are available in other storage regions, the data can be recovered using the duplicates. Otherwise, depending on the RAID level of the RAID array that the faulty region belongs to, the data in the faulty region may be recovered. For example, if the faulty region is part of a RAID1 array, the data in the faulty region may be reconstructed utilizing the mirror region. If the faulty region is part of a RAID5 array, the data in the faulty region may be reconstructed using other storage regions and parity sectors.

FIG. 2shows an example of a HDD, which may be used as one of the MRDs102in the system100.FIG. 2is a side view200of portions of an MRD that includes one disk platter201with recording media on both sides, including an upper recording surface203and a lower recording surface205. The disk drive inFIG. 2includes an upper recording head actuator207and a lower recording head actuator209, configured to control upper recording head211and lower recording head213for reading and/or writing data to the upper recording surface203and the lower recording surface205, respectively. In some cases, upper recording head211and lower recording head213can be moved by a common actuator. A servo controller215has an upper recording head servo controller217and a lower recording head servo controller219for controlling the upper recording head actuator207and the lower recording head actuator209, respectively. In some storage devices, a single actuator may be used to move all recording heads over large distances, where a secondary actuator or dual stage actuator is used for fine positioning of each individual recording head. Various other arrangements and combination of one or more multiple actuators are possible. The disk platter201is rotated by spindle motor221. The upper recording head actuator207and the lower recording head actuator209share a common axis, but can move independently of each other. AlthoughFIG. 2shows a disk drive with only a single disk platter201, other disk drives may include two or more disk platters. For a disk drive with two disk platters, there may be one or more actuators to move the recording heads for the disk platters.

The upper recording head211and lower recording head213may be positioned to radial locations on the upper recording surface203and lower recording surface205utilizing upper recording head actuator207and lower recording head actuator209, respectively. Upper recording head servo controller217and lower recording head servo controller219control the upper recording head actuator207and lower recording head actuator209, respectively. The upper recording head servo controller217and lower recording head servo controller219may receive commands from a storage controller such as storage controller104in response to requests from the processing device106to read or write data to theFIG. 2disk drive.

In another configuration, as discussed briefly above, dual stage actuators (DSAs) may be utilized in a HDD. A primary voice coil motor (VCM) actuator is used to move all recording heads over large distances, with a secondary or DSA mounted close to the recording head used for independent fine positioning of each recording head. Multiple storage regions on each surface of the MRD may provide redundancy against failure of an individual recording head secondary actuator.

FIG. 3shows a top view300of portions of theFIG. 2disk drive, including an upper recording head ramp301and a lower recording head ramp303for positioning upper recording head211and lower recording head213, which are independently controllable, into load/unload ramp positions.

TheFIG. 2disk drive may be configured as an MRD. For example, the upper recording surface203and lower recording surface205may be defined as first and second storage regions associated with different sets of failure characteristics. The upper recording surface203is associated with a first set of failure characteristics while the lower recording surface205is associated with a second set of failure characteristics. The differing failure characteristics may be due, at least in part, to the fact data is read from and written to the upper recording surface203utilizing upper recording head211while data is read from and written to the lower recording surface205utilizing lower recording head213. In some embodiments, it may be unlikely for both the upper recording head211and the lower recording head213, or for both the upper recording head actuator207and the lower recording head actuator209or upper recording head servo controller217and lower recording head servo controller219, to fail at the same time. As an example, if due to a disk defect or a mechanical shock the upper recording head207flies too close to the upper recording surface203and damages a surface coating of the upper recording surface203, it may be unlikely that the lower recording head209will simultaneously suffer a similar failure. Various other types of mechanical failure of the upper recording head211, upper recording head actuator207and upper recording head servo controller217may be unlikely to occur at the same time as mechanical failure of the lower recording head213, lower recording head actuator209and lower recording head servo controller219.

The storage regions of theFIG. 2disk drive need not be limited solely to distinctions between the upper recording surface203and the lower recording surface205. In other embodiments, different portions of the upper recording surface203may be divided into two or more storage regions. For example, it may be determined that disk read or write errors tend to accumulate in particular sectors or clusters on the upper recording surface203or lower recording surface205.

In addition, as discussed above in some embodiments an MRD may include multiple disk platters rather than a single disk platter as shown in theFIG. 2disk drive. Each platter, or each surface of each platter, may be associated with different failure characteristics. Other types of MRDs may use other types of storage in addition to or as an alternative to disk-based storage. For example, a hybrid hard drive may include a disk drive and flash memory. The disk drive and flash memory of a hybrid hard drive may have different associated failure characteristics. Different regions within flash memory may also have different associated failure characteristics.

In some embodiments, the different storage regions of an MRD may be predefined, such as at the time of manufacture based on an analysis of the physical structure of the MRD, e.g., the different recording surfaces, recording heads and other hardware, etc. In other embodiments, the different storage regions of the MRD may be user-defined, or learned by a storage controller such as storage controller104or a processing device such as processing device106based on an analysis of failure patterns of the MRD. Heuristics may be used to identify correlated storage regions associated with similar failure characteristics. The failure patterns may be obtained by storage controller104from a S.M.A.R.T. monitoring system of an MRD such as MRD102-1. In still other embodiments, a combination of predefined and user-defined storage regions may be used for a particular MRD such as MRD102-1.

FIG. 4shows a process400for storing data in at least one MRD. In step402, two or more storage regions of at least one MRD are defined, where the two or more storage regions comprise a first storage region associated with a first set of failure characteristics and at least a second storage region associated with a second set of failure characteristics different than the first set of failure characteristics. Next, in step404, at least a portion of the data that is stored in the first storage region is replicated in the second storage region.

In some embodiments, step404is performed responsive to detecting a failure in a third storage region of at least one MRD, where the third storage region has a third set of failure characteristics similar to the first set of failure characteristics. In other words, data replication or mirroring in step404may be performed for those storage regions that have similar failure characteristics to one or more failed storage regions.

Step404may be performed by a storage controller such as storage controller104, and may in some embodiments further involve detecting a failure in the first storage region and reconstructing at least a portion of the data stored in the first storage region in a third storage region of the at least one MRD utilizing the replicated data stored in the second storage region.

The first and second sets of failure characteristics may comprise information indicating susceptibility to different types of failure. Different types of failure include mechanical failure of one or more parts of the at least one MRD, such as failure of one or more recording heads of the at least one MRD, degradation of a surface coating of a storage medium of the at least one MRD, etc.

In some embodiments, the at least one MRD referred to in the process400comprises a first MRD having a first plurality of storage regions associated with respective different sets of failure characteristics and a second MRD having a second plurality of storage regions associated with respective different sets of failure characteristics. The first storage region and the second storage region in the process400may both be part of the first MRD or may both be part of the second MRD. Alternatively, the first storage region may be part of one of the first MRD and the second MRD while the second storage region is part of the other one of the first MRD and the second MRD.

Provided below are various exemplary cases wherein the first storage region and the second storage region referred to in the process400are associated with different sets of failure characteristics. It is to be appreciated, however, that various other use cases are possible.

In one case, the first storage region comprises at least a portion of a first surface of a disk platter of the at least one MRD and the second storage region comprises at least a portion of a second surface of the disk platter of the at least one MRD.

In another use case, the first storage region comprises at least a portion of a first area of one or more disk platters of the at least one MRD accessed via a first recording head of the at least one MRD and the second storage region comprises at least a portion of a second area of the one or more disk platters of the at least one MRD accessed via a second recording head of the at least one MRD.

In another use case, the first storage region comprises at least a portion of a first disk platter of the at least one MRD and the second storage region comprises at least a portion of a second disk platter of the at least one MRD.

In another use case, the at least one MRD comprises a hybrid hard drive including a HDD and a flash memory or SSD where the first storage region comprises at least a portion of the HDD and the second storage region comprises at least a portion of the flash memory or SSD.

In another use case, there may be disk defects at particular azimuthal and radial (sector) locations on a disk drive which results in head disk interactions, such as a recording head making contact with a disk. A recording head servo control track following can be affected by errors in the servo pattern, which may occur at particular sector locations of a disk. Such servo pattern errors can occur at the time the servo pattern is written onto the disk during manufacture. In such instances, the first and second storage regions may thus comprise different azimuthal and radial locations, or more generally different sector locations of a disk.

As shown inFIG. 5, computer system/server512in computing node510is shown in the form of a general-purpose computing device. The components of computer system/server512may include, but are not limited to, one or more processors or processing units516, a system memory528, and a bus518that couples various system components including system memory528to processor516.

The computer system/server512typically includes a variety of computer system readable media. Such media may be any available media that is accessible by computer system/server512, and it includes both volatile and non-volatile media, removable and non-removable media.

The system memory528can include computer system readable media in the form of volatile memory, such as random access memory (RAM)530and/or cache memory532. The computer system/server512may further include other removable/non-removable, volatile/nonvolatile computer system storage media. By way of example only, storage system534can be provided for reading from and writing to a non-removable, non-volatile magnetic media (not shown and typically called a “hard drive”), which is an example of an MRD. 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 the bus518by one or more data media interfaces. As depicted and described herein, the memory528may 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. A program/utility540, having a set (at least one) of program modules542, may be stored in memory528by 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 modules542generally carry out the functions and/or methodologies of embodiments of the invention as described herein.

Computer system/server512may also communicate with one or more external devices514such as a keyboard, a pointing device, a display524, etc., one or more devices that enable a user to interact with computer system/server512, and/or any devices (e.g., network card, modem, etc.) that enable computer system/server512to communicate with one or more other computing devices. Such communication can occur via I/O interfaces522. Still yet, computer system/server512can communicate with one or more networks such as a LAN, a general WAN, and/or a public network (e.g., the Internet) via network adapter520. As depicted, network adapter520communicates with the other components of computer system/server512via bus518. It should be understood that although not shown, other hardware and/or software components could be used in conjunction with computer system/server512. 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.

Characteristics are as Follows:

Service Models are as Follows:

Deployment Models are as Follows:

Referring now toFIG. 6, illustrative cloud computing environment650is depicted. As shown, cloud computing environment650comprises one or more cloud computing nodes610with which local computing devices used by cloud consumers, such as, for example, personal digital assistant (PDA) or cellular telephone654A, desktop computer654B, laptop computer654C, and/or automobile computer system654N may communicate. Nodes610may 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 environment650to 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 devices654A-N shown inFIG. 6are intended to be illustrative only and that computing nodes610and cloud computing environment650can communicate with any type of computerized device over any type of network and/or network addressable connection (e.g., using a web browser).

Hardware and software layer760includes hardware and software components. Examples of hardware components include: mainframes761; RISC (Reduced Instruction Set Computer) architecture based servers762; servers763; blade servers764; storage devices765; and networks and networking components766. In some embodiments, software components include network application server software767and database software768.

Virtualization layer770provides an abstraction layer from which the following examples of virtual entities may be provided: virtual servers771; virtual storage772; virtual networks773, including virtual private networks; virtual applications and operating systems774; and virtual clients775.

Workloads layer790provides 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 navigation791; software development and lifecycle management792; virtual classroom education delivery793; data analytics processing794; transaction processing795; and data mirroring processing796, which may perform one or more of the functions described above for defining MRDs, storing data on MRDs, reconstructing data in MRDs, etc.