Patent Publication Number: US-11385967-B2

Title: Method for managing backup data by having space recycling operations on executed backup data blocks

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application claims priority, under 35 U.S.C. § 119, of Chinese Patent Application No. 202010113257.3, filed Feb. 24, 2020, which is incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     Embodiments of the present disclosure relate to the field of computers, and more specifically to a method for managing backup data, an electronic device, and a computer program product. 
     BACKGROUND 
     In recent years, with the development of computer technologies, people are increasingly concerned about the security of data storage. Data backup also has become a common technique to ensure data security. As the size of data backed up by users is getting increasingly huge, storage spaces required by backup data are also becoming increasingly large. Therefore, how to effectively organize the storage of the backup data has become one of the focuses of attention at present. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present disclosure provide a scheme for managing backup data. 
     According to a first aspect of the present disclosure, a method for managing backup data is presented. This method includes: determining a number of times of space recycling operations that have been executed on a backup data block; determining, based on the number of times, a current popularity of the backup data block, the current popularity at least indicating a probability that the backup data block will be recycled in a to-be-executed space recycling operation; and moving, based on a determination that a former storage area where the backup data block is located does not correspond to the current popularity, the backup data block to a target storage area corresponding to the popularity. 
     According to a second aspect of the present disclosure, an electronic device is presented. The device includes: at least one processing unit; and at least one memory, the at least one memory being coupled to the at least one processing unit and storing instructions to be executed by the at least one processing unit, the instructions, when executed by the at least one processing unit, causing the device to execute actions, the actions including: determining a number of times of space recycling operations that have been executed on a backup data block; determining, based on the number of times, a current popularity of the backup data block, the current popularity at least indicating a probability that the backup data block will be recycled in a to-be-executed space recycling operation; and moving, based on a determination that a former storage area where the backup data block is located does not correspond to the current popularity, the backup data block to a target storage area corresponding to the popularity. 
     In a third aspect of the present disclosure, a computer program product is provided. The computer program product is stored in a non-transitory computer storage medium and includes machine-executable instructions. The machine-executable instructions, when running in a device, cause the device to execute any step of the method according to the first aspect of the present disclosure. 
     The Summary of the Invention is provided to introduce a selection of concepts in a simplified form, which will be further described in the Detailed Description below. The Summary of the Invention is neither intended to identify key features or essential features of the present disclosure, nor intended to limit the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       By description of example embodiments of the present disclosure in more detail with reference to the accompanying drawings, the above and other objectives, features, and advantages of the present disclosure will become more apparent. In the example embodiments of the present disclosure, the same reference numerals generally represent the same components. 
         FIG. 1  illustrates a schematic diagram of an example environment in which a plurality of embodiments of the present disclosure can be implemented; 
         FIG. 2  illustrates a schematic diagram of an example space recycling process; 
         FIG. 3  illustrates a flowchart of a process of managing backup data according to an embodiment of the present disclosure; 
         FIG. 4  illustrates a schematic diagram of moving the backup data according to an embodiment of the present disclosure; 
         FIG. 5  illustrates a flowchart of an example process of moving the backup data according to an embodiment of the present disclosure; and 
         FIG. 6  illustrates a schematic block diagram of an example device that may be configured to implement embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. The preferred embodiments of the present disclosure are shown in the accompanying drawings. However, it should be understood that the present disclosure can be implemented in various forms and should not be limited to the embodiments set forth herein. In contrast, these embodiments are provided to make the present disclosure more thorough and complete, and fully convey the scope of the present disclosure to those skilled in the art. 
     The term “including” and variants thereof used herein indicate open-ended inclusion, i.e., “including, but not limited to.” Unless specifically stated, the term “or” indicates “and/or.” The term “based on” indicates “based at least in part on.” The terms “an example embodiment” and “an embodiment” indicate “at least one example embodiment.” The term “another embodiment” indicates “at least one additional embodiment.” The terms “first,” “second,” and the like may refer to different or identical objects. Other explicit and implicit definitions can be further included below. 
       FIG. 1  shows a schematic diagram of environment  100  in which embodiments of the present disclosure may be implemented. As shown in  FIG. 1 , environment  100  includes computing device  110  and backup storage apparatus  120 . Backup storage apparatus  120  may include a plurality of storage blocks  130 . Each storage block  130  may store backup data block  135  of a predetermined size. Computing device  110  can manage organization of backup data block  135  in backup storage apparatus  120 . 
     For example, backup data block  135  in backup storage apparatus  120  may be invalid due to backup expiring. As an example, computing device  110  may set up a rule according to which backup data block  135  will be marked as invalid after the backup data block has not been cited by any backup file for a period of time. Since backup storage apparatus  120  is always allocated or released with storage block  130  as a unit in a unified way, computing device  110  can release a storage space occupied by invalid backup data block  135  through a space recycling process (e.g., trash recycling).  FIG. 2  shows schematic diagram  200  of a space recycling process according to an example. 
     As shown in  FIG. 2 , storage block  130 - 1  includes a plurality of backup data blocks  212 - 228 , and storage block  130 - 2  includes a plurality of backup data blocks  232 - 248 , where backup data blocks  220 ,  224 ,  226 ,  234 ,  240 ,  242 ,  244 ,  246 , and  248  shown by slashes indicate that these backup data blocks have already been in an invalid state due to backup expiring or backup being deleted. In the space recycling process, computing device  110 , e.g., may apply for new storage block  210 , and write backup data blocks  212 ,  214 ,  216 ,  218 ,  222 ,  228 ,  232 ,  236 , and  238  that are not marked as invalid in former storage block  130 - 1  and storage block  130 - 2  in new storage block  210 . Then, computing device  110  can release former storage block  130 - 1  and  130 - 2 , thereby implementing recycling of spaces. 
     Since computing device  110  needs to apply for and recycle spaces with the storage blocks as units, such that in the space recycling process, computing device  110  needs to rewrite some of the backup data blocks. For example, for an example in  FIG. 2 , if storage block  210  needs to merge valid backup data blocks with another storage block in a new space recycling process, but for example, backup data block  212  is still marked as a valid state. In this case, backup data block  212  will be rewritten in a new storage block. In a backup system, backup data blocks are usually randomly organized, such that relatively stable backup data blocks such as backup data block  212  may undergo repeated rewriting in the space recycling process. 
     At present, more and more high-performance storage apparatuses (e.g., SSD) are used as backup storage apparatus  120 . Such high-performance storage apparatuses generally have better performance, but generally tend to have further limited number of writable times. Repeated rewriting of the backup data blocks will seriously affect usable life of backup storage apparatus  120 , which is not desired by users. 
     According to the embodiments of the present disclosure, a scheme of managing backup data is provided. In this scheme, a number of times of space recycling operations that have been executed on a backup data block is determined, and is subsequently used for determining a current popularity of the backup data block, where the current popularity at least indicates a probability that the backup data block will be recycled in a to-be-executed space recycling operation. When a former storage area where the backup data block is located does not correspond to the current popularity, the backup data block will be moved to a target storage area corresponding to the popularity. In this way, backup data blocks are always organized based on popularities, such that backup data blocks that are more probably recycled will be more probably gathered into the same storage area in the space recycling process, such that a storage area of a backup data block with a lower storage popularity is more stable, thereby reducing data rewriting caused by subsequent space recycling. 
     A process of storage management according to an embodiment of the present disclosure will be described below with reference to  FIG. 3  to  FIG. 5 .  FIG. 3  shows a flowchart of process  300  of managing backup data according to some embodiments of the present disclosure. Process  300 , e.g., may be implemented by computing device  110  as shown in  FIG. 1 . 
     In block  302 , computing device  110  determines a number of times of space recycling operations that have been executed on backup data block  135 . For example, computing device  110  may record, for each backup data block  135 , the number of times of space recycling operations undergone by the backup data block. When backup data block  135  has undergone a plurality of times of space recycling operations, but has not yet been recycled, it may indicate that the backup data block is relatively stable in the backup system. 
     It should be understood that the process of block  302  may be executed periodically, or may be executed after each space recycling operation. Furthermore, the process of block  302  may also be executed in response to an administrator&#39;s request. It should be understood that the above examples are merely illustrative, rather than limiting, and the present disclosure is not intended to limit the examples. 
     In block  304 , computing device  110 , based on the number of times, determines a current popularity of the backup data block, where the current popularity at least indicates a probability that the backup data block will be recycled in a to-be-executed space recycling operation. 
     In some embodiments, computing device  110  may determine the current popularity based on comparison between the number of times and a preset number threshold. Specifically, in some embodiments, when determining that the number of times is greater than or equal to the number threshold, computing device  110  may determine the current popularity as a preset value. For example, when the number of times is greater than the preset number threshold (e.g., 10 times), computing device  110  may determine the current popularity of the backup data block, e.g., as 0, to indicate that the backup data block is very stable, and will also be less likely to be recycled later. 
     In some embodiments, when determining that the number of times is less than the number threshold, computing device  110  may determine the current popularity based on a difference between the number of times and the number threshold. In some embodiments, the computing device  110 , e.g., may determine the current popularity of the backup data block based on the following equation (1): 
     
       
         
           
             
               
                 
                   
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     C m  represents the number threshold, C represents the number of times of space recycling operations that have been executed on backup data block  135 , N represents a number of groups of preset storage areas, and Int represents a rounding-down function. It should be understood that both C m  and N are parameters that may be adjusted based on actual needs. 
     For example, taking C m  being set as 10, and N being set as 5 as an example, if the backup data block has undergone 10 times of backups (i.e., C is 10), then computing device  110  may determine that the current popularity of the backup data block is 0. If another backup data block has undergone 5 times of backups, then computing device  110  may determine that the current popularity of another backup data block is Int ((10−5)/10*5)+1=3. In this way, for each backup data block, a current popularity thereof can be determined. It should be understood that all the above specific values are merely illustrative, any suitable value may be used as the number threshold or the number of groups, and the present disclosure is not intended to limit the specific values. 
     In block  306 , computing device  110  moves the backup data block to a target storage area corresponding to the popularity, based on a determination that the former storage area where the backup data block is located does not correspond to the current popularity. 
     In some embodiments, computing device  110  can pre-organize a space in backup storage device  120  into a plurality of different storage areas, one of which may include one or more storage blocks. For example, computing device  110  may pre-apply for using a plurality of different continuous spaces as different storage areas. Furthermore, compute device  110  can associate different storage areas with different popularities, such that backup data blocks with the same popularity are always stored in the same storage area. 
     Taking  FIG. 4  as an example,  FIG. 4  shows a schematic diagram  400  of moving backup data according to an embodiment of the present disclosure. As shown in  FIG. 4 , backup storage device  120  may include different storage areas  410  and  420 , where, e.g., storage area  410  is associated with a lower popularity (e.g., 1), while storage area  420  is associated with a higher popularity (e.g., 2). 
     In some embodiments, current popularities of backup data blocks may be updated along with a new space recycling operation. In this case, the backup data bocks need to be moved to a new storage area. Specifically, computing device  110  first may determine a former popularity corresponding to the former storage area. 
     Taking backup data blocks  458  and  466  in  FIG. 4  as an example, a current popularity of backup data blocks  458  and  466  is determined as 1 based on Equation (1) after undergoing a new space recycling process. A pre-determined former popularity of the backup data blocks is a popularity (e.g., 2) corresponding to storage area  450 . When determining that the former popularity is different from the current popularity, computing device  110  can determine that the former storage area where the backup data block is located does not correspond to the current popularity. In this case, computing device  110  can move backup data blocks  458  and  466 . 
     A specific process of moving a backup data block will be described below with reference to  FIG. 5 .  FIG. 5  shows a flowchart of an example process of moving backup data according to an embodiment of the present disclosure. As shown in  FIG. 5 , in block  502 , computing device  110  can determine a target storage area corresponding to a current popularity from a group of preset storage areas. Further taking backup data blocks  458  and  466  in  FIG. 4  as an example, after determining that their current popularity is 1, computing device  110  can determine a storage area corresponding to a popularity of 1 from a group of storage areas corresponding to different popularities, as storage area  410 . 
     In block  504 , computing device  110  can move the backup data blocks to an available storage space in the target storage area. As shown in the figure, computing device  110  can allocate a new storage space in storage area  410  for storing data in backup data blocks  458  and  466 , i.e., forming new backup data blocks  430  and  432 . Furthermore, computing device  110  can mark a storage space for storing data blocks  458  and  466  in storage area  450  as invalid. It should be understood that the specific values on popularity in the above examples are illustrative, and the present disclosure is not intended to limit the specific values. 
     Since storage area  410  is a larger pre-allocated storage space, computing device  110  can write new backup data blocks  430  and  432  successively from bottom of the available space, and will not affect other existing backup data blocks. Generally, only when a proportion of invalid backup data blocks in a storage block reaches a preset threshold, can computing device  110  execute merging and release of storage blocks. Therefore, considering that each of the backup data blocks in storage area  410  has a relatively low probability to be invalid in future space recycling operations, a probability that a proportion of invalid backup data blocks in storage area  410  exceeds the threshold will be very low, such that the backup data blocks in the storage area do not need to be rewritten. 
     Considering that some of the backup data blocks in storage area  410  with a relatively low popularity may still be marked as invalid, e.g., due to backup file deletion, in some embodiments, for different storage blocks in the same storage area  410 , computing device  110  can still release spaces of the storage blocks by merging and writing, as in a conventional way. For example, computing device  110  can scan invalid backup data blocks in each storage block of the same storage area  410 , to determine whether the proportion of invalid backup data blocks exceeds the threshold. When determining that the proportion of invalid backup data blocks exceeds the threshold, computing device  110  can apply for a new storage block in the storage area, to which valid backup data blocks in the storage block exceeding the threshold are written, and then release the storage block previously exceeding the threshold. In this way, computing device  110  can improve a space utilization in the same storage area  410 . 
     According to the method described above, embodiments of the present disclosure can organize different storage areas based on popularities. In this way, when undergoing a new space recycling operation, data stored in a storage area associated with a relatively low popularity are all backup data blocks with a relatively low popularity. Thus, these backup data blocks will be more likely to remain valid in future space recycling operations, such that an rewriting operation will occur at a relatively low probability for the storage area associated with a relatively low popularity in subsequent space recycling operation processes. Compared with the conventional random storage mode, the embodiments of the present disclosure can extend usable life of backup storage devices. 
       FIG. 6  shows a schematic block diagram of an example device  600  that may be configured to implement embodiments of the present disclosure. For example, computing device  110  according to the embodiments of the present disclosure may be implemented by device  600 . As shown in the figure, device  600  includes processing unit (CPU)  601 , which may execute various appropriate actions and processing in accordance with computer program instructions stored in read-only memory (ROM)  602  or computer program instructions loaded onto random access memory (RAM)  603  from storage unit  608 . RAM  603  may further store various programs and data required by operations of device  600 . CPU  601 , ROM  602 , and RAM  603  are connected to each other through bus  604 . Input/output (I/O) interface  605  is also connected to bus  604 . 
     A plurality of components in device  600  is connected to I/O interface  605 , including: input unit  606 , such as a keyboard and a mouse; output unit  607 , such as various types of displays and speakers; storage unit  608 , such as a magnetic disk and an optical disk; and communication unit  609 , such as a network card, a modem, and a wireless communication transceiver. Communication unit  609  allows device  600  to exchange information/data with other devices via a computer network such as the Internet and/or various telecommunication networks. 
     The processes and processing described above, such as process  300 , may be executed by processing unit  601 . For example, in some embodiments, process  300  may be embodied as a computer software program that is tangibly included in a machine-readable medium, such as storage unit  608 . In some embodiments, some of or all the computer program can be loaded and/or installed onto device  600  via ROM  602  and/or communication unit  609 . When the computer program is loaded into RAM  603  and executed by CPU  601 , one or more actions of process  300  described above may be executed. 
     The present disclosure may be a method, an apparatus, a system, and/or a computer program product. The computer program product may include a computer-readable storage medium with computer-readable program instructions for executing various aspects of the present disclosure loaded thereon. 
     The computer-readable storage medium may be a tangible device that can retain and store instructions used by an instruction executing device. Examples of the computer-readable storage medium may include, but are not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (a non-exhaustive list) of the computer-readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punched card or an in-groove raised structure with instructions stored thereon, and any suitable combination thereof. The computer-readable storage medium used herein is not construed as transient signals themselves, such as radio waves or other freely propagated electromagnetic waves, electromagnetic waves propagated through waveguides or other transmission media (e.g., optical pulses through fiber-optic cables), or electrical signals transmitted through wires. 
     The computer-readable program instructions described here can be downloaded from a computer-readable storage medium to various computing/processing devices, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, optical fiber transmission, wireless transmission, routers, firewalls, switches, gateway computers, and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer-readable program instructions from the network and forwards the computer-readable program instructions, such that the computer-readable program instructions are stored in the computer-readable storage medium in each computing/processing device. 
     The computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages. The programming languages include object-oriented programming languages such as Smalltalk and C++, and also include conventional procedural programming languages such as the “C” language or similar programming languages. The computer-readable program instructions can be executed entirely on a user computer, partly on the user computer, as a separate software package, partly on the user computer and partly on a remote computer, or entirely on the remote computer or a server. In the case where a remote computer is involved, the remote computer can be connected to a user computer through any kind of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (e.g., connected through the Internet using an Internet service provider). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), is customized by utilizing state information of the computer-readable program instructions. The computer-readable program instructions may be executed by the electronic circuit to implement various aspects of the present disclosure. 
     Various aspects of the present disclosure are described here with reference to the flowcharts and/or block diagrams of the method, apparatus (system), and computer program product according to the embodiments of the present disclosure. It should be understood that each block in the flowcharts and/or block diagrams as well as a combination of blocks in the flowcharts and/or block diagrams may be implemented by the computer-readable program instructions. 
     These computer-readable program instructions can be provided to a processing unit of a general-purpose computer, a special-purpose computer, or another programmable data processing apparatus to produce a machine, such that these instructions, when executed by the processing unit of the computer or another programmable data processing apparatus, generate an apparatus for implementing the functions/actions specified in one or more blocks in the flowcharts and/or block diagrams. The computer-readable program instructions may also be stored in a computer-readable storage medium. These instructions cause the computer, the programmable data processing apparatus, and/or another device to operate in a particular manner, such that the computer-readable medium storing the instructions includes a manufactured product, which includes instructions for implementing various aspects of the functions/actions specified in one or more blocks in the flowcharts and/or block diagrams. 
     The computer-readable program instructions may also be loaded onto a computer, another programmable data processing apparatus, or another device, such that a series of operation steps are performed on the computer, another programmable data processing apparatus, or another device to produce a computer-implemented process. Thus, the instructions executed on the computer, another programmable data processing apparatus, or another device implement the functions/actions specified in one or more blocks in the flowcharts and/or block diagrams. 
     The flowcharts and block diagrams in the accompanying drawings show the architectures, functions, and operations of possible implementations of the system, method, and computer program product according to a plurality of embodiments of the present disclosure. In this regard, each block in the flowcharts or block diagrams may represent a module, a program segment, or part of an instruction, said module, program segment, or part of an instruction including one or more executable instructions for implementing specified logical functions. In some alternative implementations, the functions noted in the blocks may occur in a sequence different from that shown in the figures. For example, any two blocks presented in succession may actually be executed substantially in parallel, or they may sometimes be executed in a reverse sequence, depending on the functions involved. It should be further noted that each block in the block diagrams and/or flowcharts as well as a combination of blocks in the block diagrams and/or flowcharts may be implemented by using a dedicated hardware-based system executing specified functions or actions, or by a combination of dedicated hardware and computer instructions. 
     The embodiments of the present disclosure have been described above. The above description is illustrative, rather than exhaustive, and is not limited to the disclosed embodiments. Numerous modifications and alterations are apparent to those of ordinary skills in the art without departing from the scope and spirit of various illustrated embodiments. The selection of terms used herein is intended to best explain the principles and practical applications of the embodiments or improvements of the technologies on the market, or to cause other persons of ordinary skills in the art to understand the embodiments disclosed herein.