WO2015127758A1

WO2015127758A1 - Backup file data retransmission method, device and system

Info

Publication number: WO2015127758A1
Application number: PCT/CN2014/083341
Authority: WO
Inventors: 郭伟; 陈�峰; 陈霁
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-02-27
Filing date: 2014-07-30
Publication date: 2015-09-03
Also published as: CN104883265A

Abstract

Provided are a backup file data retransmission method, device and system, the method comprising: receiving a backup request used for triggering a network data management protocol (NDMP) to back up a file to be backed up; with triggering of the backup request, determining second part of content not successfully transmitted at a transmission interruption according to the contextual information at the transmission interruption before the transmission of the file to be backed up and the first part of content stored before the transmission interruption, the first part of the content and the second part of the content constituting the file to be backed up; continuing to transmit the second part of the content at the point of transmission interruption. The technical solution of the present invention can solve the technical problems in the relevant art of a long interval of data backup and recovery and the affected user experience caused by the incapability of supporting breakpoint resumption in an NDMP-based data backup process, shortening the time interval of re-backup after the interruption of data backup.

Description

The present invention relates to the field of mobile communications, and in particular, to a data retransmission method, apparatus, and system for a backup file. BACKGROUND OF THE INVENTION The Network Data Management Protocol (DMP) is an open standard for centralized control and management of enterprise data. The DMP architecture enables backup application vendors to control native backup and recovery devices on network attached storage servers, such as Network Attached Storage (NAS) devices. A technique is provided in existing DMP technology to provide a common interface between any backup software application and a NAS device. In this way, application vendors can support a variety of NAS devices without having to redesign expensive programming logic. Moreover, NAS device vendors can seamlessly collaborate with any DMP-compatible application.

NDMP allows backup servers running DMP-compatible applications to directly back up and restore multiple NAS Filers. The software application uses DMP to send a request to the NAS Filer to invoke the backup and recovery process. During the backup operation, information about the backed up files (such as backup file history information) is sent from the NAS Filer to the software application running on the backup server. At this point, the actual file will be sent from the NAS Filer to the target backup location. However, in the process of providing data backup, if the file transmission is interrupted, the backup server needs to re-initiate the backup request, and the file is transmitted from the beginning. In this way, if the network is unstable during the backup process, the data backup and recovery interval may be too long, which may affect the user experience. In view of the above problems in the related art, an effective solution has not yet been proposed. SUMMARY OF THE INVENTION In the related art, the present invention provides a backup file due to technical problems such as a user experience and other problems caused by the fact that the data backup and recovery time interval is not supported during the data backup process based on the DMP protocol. The data retransmission method and apparatus, system, to at least solve the above problems. In order to achieve the above object, according to an embodiment of the present invention, a data retransmission method for a backup file is provided, including: receiving a backup request for triggering backup of a file to be backed up by using a network data management protocol NDMP; Under the trigger of the request, the transmission of the file to be backed up before the current transmission is interrupted. And the second part of the content that is not successfully transmitted at the interruption of the transmission, where the first part of the content and the second part of the content constitute the file to be backed up; At the interruption of the transmission, the transmission of the second portion of content continues. Preferably, before receiving the backup request for triggering the backup of the file to be backed up by using the DMP protocol, the method further includes: when the transmission of the file to be backed up is interrupted before the current transmission, according to the context information and the file to be backed up The file description information establishes a data retransmission entry. Preferably, the file description information includes at least one of the following: file size information and file identification information of the file to be backed up. Preferably, the file identification information includes at least one of the following: a file attribute of the file to be backed up, and summary information of the file to be backed up. Preferably, the second part of the content that is not successfully transmitted at the transmission interruption is determined according to the context information of the to-be-backed file at the transmission interruption before the current transmission and the first part of the content stored before the transmission interruption, including: Querying the file description information of the backup file; querying, according to the file description information, whether the file description information of the file to be backed up exists in the data retransmission entry; if yes, retransmitting the entry according to the data Determining the relationship between the context information and the content of the first part, and determining the content of the second part. In order to achieve the above object, according to still another embodiment of the present invention, a data retransmission apparatus for a backup file is provided, including: a receiving module, configured to receive a trigger for triggering backup of a file to be backed up by using a network data management protocol DMP; a backup request, configured to, under the trigger of the backup request, determine the interruption in the transmission according to the context information of the to-be-backed file at the transmission interruption before the current transmission and the first part of the content stored before the transmission interruption The second part of the content is not successfully transmitted, wherein the first part of content and the second part of content constitute the file to be backed up; the transmission module is configured to continue to transmit the second part at the interruption of the transmission content. Preferably, the method further includes: an establishing module, configured to establish a data retransmission entry according to the context information and the file description information of the file to be backed up when the transmission of the file to be backed up is interrupted before the current transmission. Preferably, the establishing module is configured to: when the file description information includes at least one of the following, establish a data retransmission entry according to the context information and file description information of the file to be backed up: File size information and file identification information. Preferably, the determining module includes: an obtaining unit, configured to acquire file description information of the file to be backed up; and a query unit, configured to query whether the data retransmission entry exists in the file description information according to the file description information The file description information of the file to be backed up; the determining unit is configured to: according to the file description information of the file to be backed up, according to the relationship between the context information in the data retransmission entry and the content of the first part, Determining the second part of the content. In order to achieve the above object, according to still another embodiment of the present invention, a data retransmission system for backing up files is provided, including: a backup server, configured to initiate a backup request for triggering backup of a file to be backed up by using the DMP protocol; a source server, configured to, according to the backup request, determine that the context information of the file to be backed up before the transmission is interrupted and the first part of the content stored before the transmission interruption, determining that the transmission is not successfully transmitted at the interruption And in the file to be backed up, in addition to the second part of the content of the first part of content, and continue to send the second part of content to the destination server; the destination server is configured to receive the second part of content sent by the source server . According to the present invention, under the DMP protocol, according to the context information of the file to be backed up at the transmission interruption and the first part of the content stored before the transmission interruption, the second part of the content that was not successfully transmitted at the transmission interruption is determined, and the transmission is continued. The technical means of the second part of the content solves the technical problems of the user experience, such as the data backup and recovery time interval caused by the failure to support the resume transmission in the DMP-based data backup process. Reduced the time interval for re-backup after data backup is interrupted. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a flowchart of a data retransmission method of a backup file according to an embodiment of the present invention; FIG. 2 is a flowchart of a data retransmission method of a backup file according to a preferred embodiment of the present invention; A further flowchart of a data retransmission method of a backup file according to a preferred embodiment of the present invention; FIG. 4 is a structural block diagram of a data retransmission apparatus of a backup file according to an embodiment of the present invention; FIG. 5 is a backup file according to an embodiment of the present invention. FIG. 6 is a block diagram showing a structure of a data retransmission system for backing up files according to an embodiment of the present invention; FIG. 7 is another block diagram of a data retransmission system for backing up files according to an embodiment of the present invention; Structure diagram. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. Other features and advantages of the invention will be set forth in the description which follows, and The objectives and other advantages of the invention will be realized and attained by the <RTI 1 is a flow chart of a data retransmission method of a backup file according to an embodiment of the present invention. As shown in FIG. 1, the method includes: Step S102 to Step S106, Step S102, receiving a backup request for triggering backup of a backup file by using a network data management protocol NDMP; Step S104, under the trigger of the backup request, according to The context information of the backup file before the transmission is interrupted and the first part of the content stored before the transmission interruption determines the second part of the content that is not successfully transmitted at the interruption of the transmission, wherein the first part content and the second part content constitute The file to be backed up; Step S106, continuing to transmit the second part of the content at the interruption of the transmission. Through the above steps, under the DMP protocol, according to the context information of the file to be backed up at the transmission interruption and the first part of the content stored before the transmission interruption, the second part of the content that was not successfully transmitted at the transmission interruption is determined, and the transmission continues. The technical means of the second part of the content solves the problem that the DMP protocol cannot support the data retransmission from the breakpoint after the backup request is re-initiated, which may result in data backup if the network is unstable during the data backup process. The recovery time interval is too long, which affects the technical experience of the user experience, and greatly shortens the time interval for re-backup after the data backup is interrupted. Before the step S102, the following process may be performed: when the transmission of the file to be backed up is interrupted before the current transmission, the data retransmission entry is established according to the context information and the file description information of the file to be backed up, optionally, The executor of the above-mentioned data retransmission entry can be an NDMP source server. The NDMP source server can be understood as an NDMP server. Optionally, the file description information includes at least one of the following: file size information and file identification information of the file to be backed up, where the file identification information includes at least one of the following: a file attribute of the file to be backed up, and summary information of the file to be backed up, The file size information and the file identification information are added in the process of interacting with the backup file information in the NDMP client (which can be understood as a backup server). The following implementation process can better understand how to establish a data retransmission entry. After the backup file is interrupted, the NDMP source server saves the context information of the interruption, and sends a file attribute/complete file summary carrying the download interruption file ( The NDMP source server establishes a data retransmission entry according to the queried file attribute/complete file summary, and the data retransmission entry further includes the query request of the file identifier information in the foregoing embodiment. The context information at the interruption, and the data retransmission entry is associated with the data cache information at the time of the interruption and saved. In order to better understand the above process, the following description will be made in conjunction with a preferred embodiment. The preferred embodiment of the present invention mainly shows how to establish a data retransmission entry. As shown in FIG. 2, the specific steps are as follows: Step S202: The NDMP backup server adds a file summary field in the process of performing backup file information interaction. The file summary field shown here is specifically: one or several file verification algorithms are selected, and the NDMP backup server obtains a file summary of the file according to the file verification algorithm, and adds it to the file entry saved in the NDMP source server. . The algorithm of the above backup file may be a Cyclic Redundancy Check (referred to as a Cyclic Redundancy Check, referred to as

CRC) 32 check algorithm, Message Digest (MD) 5 algorithm. The NDMP backup server uses the same algorithm to obtain a summary of added files, which ensures that different file systems can add the same file digest, which can increase the probability of finding the file digest of the interrupted file, and the compatibility should be improved. Step S202 may further include adding a file size field to the file to ensure that the uniqueness of the interrupt file is found. Step S204: The NDMP source server saves the context information at the interruption, and sends a query request carrying the file attribute/complete file summary of the download interruption file; the cause of the interruption may be communication abnormality or backup server failure. When the complete file information can be queried, if the interrupted file is found to be found, step S206 is performed, S208. If the query is not found, the abnormal processing branch is entered, and it is considered that the file information is destroyed, then the process proceeds to step S210 to end the interrupt. The processing flow may enter the NDMP backup recovery process. Step S206: The NDMP source server establishes a data retransmission entry, and the content included in the entry includes file summary information of the interrupt file, and context information of the interrupted file. The entry can be designed to save multiple interrupt file summary information, so that data retransmission of multiple files can be supported. The number of specific data retransmission entries can be determined by the size of the data cache. Step S208: The data cache saves the upper part of the interrupt file and associates with the information corresponding to the data retransmission entry. Step S210: End the interrupt processing flow. A further improvement of the foregoing technical solution in the embodiment of the present invention is that the establishment of the association may generate a cache file ID of the upper part of the interrupt file, and then find a corresponding entry in the data retransmission entry according to the file summary of the interrupt file. Associate the cache file ID with the corresponding entry for data retransmission. In this embodiment, the second part of the content that is not successfully transmitted at the transmission interruption is determined according to the context information of the to-be-backed file at the transmission interruption before the current transmission and the first part of the content stored before the transmission interruption, including: Obtaining the file description information of the file to be backed up; querying, according to the file description information, whether the file description information of the file to be backed up exists in the data retransmission entry; if yes, retransmitting the context information in the entry according to the data The association relationship of the first part of the content above determines the content of the second part. Further, when the client initiates the same file backup again, the NDMP client receives the queried file identification information according to the initiated file backup request, and then searches for the data retransmission entry according to the file identification information. In step S104, if the file that was last interrupted is found in the data retransmission entry, then in step S106, the NDMP source server retransmits the context information and the cache of the file in the entry according to the data retained by itself, and re-sum The NDMP destination server establishes a data connection. The content of the interrupt in the data cache is determined by the context information when the file is interrupted. If the file information in the new request is not found in the data retransmission table, the data retransmission process is terminated, and the normal file backup process is started. In the process of the foregoing embodiment of the present application, after the data retransmission entry is established, when the file backup request is initiated again, as shown in FIG. 3, the detailed process is as follows: Step S302: The backup server receives a new file backup request. , initiating a query request for the data retransmission entry. The purpose of the request is to determine whether the new file backup request is a file that was interrupted by the backup. Step S304: After receiving the query request, the NDMP source server queries the saved data retransmission entry to check whether there is an entry that meets the requirements. If the data retransmission entry has a corresponding entry, the process proceeds to step S306. ~S310. Otherwise, it is considered as a new backup file request, ends the data retransmission process, and returns to the backup server to enter the normal NDMP file backup process. The data retransmission entry query in step S304 includes: comparing the file complete summary information and file size carried in the file query request with the file summary information held by the data retransmission entry to determine the file to be retransmitted . Here, steps S306 to S310 complete the specific data retransmission step. Step S306: The NDMP source server determines the content of the undownloaded part in the retransmission file according to the association between the context information of the file in the retransmission entry and the content on the file in the cache. Step S308: The NDMP source server and the NDMP destination server re-establish a data connection, and the cache continues data backup from the data interruption point to enter a normal data transmission process. Step S310: End the data retransmission process. In order to better understand the data retransmission process of the backup file in the foregoing embodiment, a data retransmission device for backing up the file is also provided in the embodiment, which is used to implement the foregoing embodiment and the preferred embodiment. The description will not be repeated, and the modules involved in the device will be described below. As used below, the term "module" may implement a combination of software and/or hardware of a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware, is also possible and conceivable. 4 is a structural block diagram of a data retransmission apparatus of a backup file according to an embodiment of the present invention. As shown in FIG. 4, the apparatus includes: a receiving module 42 configured to receive a backup request for triggering backup of a backup file by using a network data management protocol NDMP; a determining module 44, connected to the receiving module 42, configured to be in the above backup Under the trigger of the request, according to the context information of the to-be-backed file at the transmission interruption before the current transmission and the first part of the content stored before the transmission interruption, determining the second part of the content that was not successfully transmitted at the transmission interruption, wherein The first part of the content and the second part of the content constitute the file to be backed up; the transmission module 46 is connected to the determining module 44, and is arranged to continue to transmit the second part of the content at the transmission interruption. A further improvement of the foregoing technical solution in the embodiment of the present invention is that, as shown in FIG. 5, the foregoing apparatus further includes: an establishing module 48, which is connected to the receiving module 42 and the determining module 44, and is set to be before the file to be backed up before the current transmission. When the transmission is interrupted, a data retransmission entry is established according to the context information and the file description information of the file to be backed up. The file description information includes at least one of the following: file size information and file identification information of the file to be backed up. In a preferred embodiment of the present embodiment, as shown in FIG. 5, the determining module 44 may further include: an obtaining unit 442, configured to acquire file description information of the file to be backed up; and a query unit 444, connected to the obtaining unit 442, And determining, according to the file description information, whether the file description information of the file to be backed up exists in the data retransmission entry; the determining unit 446 is connected to the query unit 444, and is set to be in the presence of the file description information of the file to be backed up, And determining, according to the relationship between the foregoing context information in the data retransmission entry and the content of the first part, determining the content of the second part. It should be noted that the flow of the method in the above-described embodiments and the preferred embodiments of the present invention and the directions in the block diagrams are only for better explanation of the present invention and do not constitute an undue limitation of the present invention. Through the functions of the above modules, under the DMP protocol, according to the context information of the file to be backed up at the transmission interruption and the first part of the content stored before the transmission interruption, the second part of the content that was not successfully transmitted at the transmission interruption is determined, and The technical means of continuing to send the second part of the content solves the related art, because the NDMP protocol cannot support the data retransmission from the breakpoint after the backup request is re-initiated, thereby causing the network not to be in the data backup process. Stabilization may result in long data backup and recovery intervals, affecting user experience and other technical issues, and greatly shortening the time interval for re-backup after data backup is interrupted. The embodiment of the present invention further provides a data retransmission system for backing up a file. As shown in FIG. 6, the method includes: a backup server 62 connected to the source server 64, and configured to initiate a backup for using the NDMP protocol to treat the backup file. a backup server; the source server 64 is connected to the destination server 66, and is configured to, according to the backup request, trigger the context information of the file to be backed up before the transmission and the first part of the content stored before the transmission interruption, Determining that the second portion of the content of the first part of the content is not successfully transmitted in the file to be backed up, and continuing to send the second part of the content to the destination server; the destination server 66 is configured to receive the content sent by the source server The second part of the above content. It should be noted that the above connection manner is only a preferred mode of the embodiment of the present invention, and does not constitute an undue limitation to the present invention. FIG. 7 is still another structural block diagram of a data retransmission system for backing up files according to a preferred embodiment of the present invention. As shown in FIG. 7, the system includes a NAS Filer source, a NAS Filer destination, and an NDMP backup server (which may be a direct memory access). (Direct Memory Access, referred to as DMA)), data connection module, data cache module. The NDMP backup server is used to add the file summary information, and is responsible for initiating a data retransmission request query to the NAS filer. When receiving the information that fails to query the retransmission entry, the NDMP backup server is responsible for entering the normal file backup process. The NDMP backup server includes two modules: a summary adding module 72 and a retransmission initiating query module 74. The summary adding module 72: in the normal NDMP file backup interaction information, adding a file summary field for selecting a file verification algorithm, using the selected file verification algorithm to obtain a file summary; and during the backup file information interaction process Add a file summary of the file to the entry corresponding to the file. The retransmission initiation query module 74: When the file backup request is initiated, the module initiates a query request to the data retransmission entry module of the NDMP source server, and the data source server determines whether to enter the data retransmission process according to the query result of the entry. .

The NAS Filer is responsible for handling the specific operations of data retransmission, and mainly includes three large modules, a data retransmission entry module 76, a data retransmission module 78, and a data connection module 82. The data retransmission entry module 76: establishes a data retransmission entry when the file backup is interrupted; when the file backup is initiated, completes the selection of the data retransmission entry. The data retransmission entry module 76 includes a data retransmission entry 762 and a data retransmission entry selection module 764. The data retransmission establishing module 762 creates a complete digest and context information of the received interrupt data file into a table entry, and associates with the file portion of the data cache. The data retransmission entry creation module 762: when the file backup is interrupted, save the context information of the interruption, and establish a data retransmission entry according to the queried file attribute/complete file summary, where the data retransmission entry further includes an interrupt. Contextual information at the place. At the same time, the data retransmission entry is associated with the data cache information when the transmission is interrupted and saved. The data retransmission entry selection module 764: when the file backup is initiated, the NDMP client re-transmits the query request of the initiating query module, and finds whether there is a matching entry in the entry, and if there is a matching entry, Send the entry information to the data retransmission module in the data transmission module. If there is no matching entry, the data retransmission process is terminated, and the normal file backup process is entered. After receiving the retransmission request, select the same entry of the file size and file summary information and the interrupt file. Associated with the cache file and sent to the data retransmission module for data retransmission. The data retransmission module 78: after receiving the entry information, determining the file retransmission content according to the file summary information, the file context information, and the content of the file before the interruption stored in the cache, and then NDMP The destination server establishes a data connection. The data cache module 80: saves the interrupted file content during the file transfer interruption process, and associates with the data entry. Part of the file before the interruption is provided during data retransmission. The data connection module 82: is responsible for data transmission between the NDMP source and the destination server. During the file backup process, it is responsible for finally storing the data files in the cache to the NDMP destination server. It should be noted that the NAS Filer source and the NAS Filer destination can be uniformly understood as the NDMP server. In the process of data retransmission, it is mainly used for data re-establishment entry establishment and data connection. Further, the NDMP server side includes two modules: a data retransmission entry module 76 and a data retransmission module 78. The method and system for data retransmission of a backup file provided by the present invention establish a data retransmission entry when the file backup is interrupted, and save the cached data. When the file is backed up, the data is retransmitted according to the data retransmission table entry and the cache data. It can greatly reduce the time interval for file backup interruption and retransmission, and avoid the long-term file backup time caused by network instability, which affects the customer experience. In summary, the embodiments of the present invention have the following advantages and features: The data retransmission entry is created by using a file attribute/complete file summary (corresponding to the file identification information in the foregoing embodiment) and the interrupt file context information, and is excluded. The retransmitted file is the same as the file that downloads the retransmission file summary but the file content is irrelevant, ensuring that the undownloaded part of the required file is retransmitted. The data retransmission design of the NDMP server does not distinguish between the far end and the destination end. It can complete the interrupt data retransmission during file backup and file recovery without redesigning the data retransmission process of the file recovery process. In the embodiment of the present invention, because the data cache is saved in the memory, the data retransmission only supports the NDMP backup server failure, the communication failure between the networks, and the data backup caused by the data connection failure is interrupted, if the NDMP source server is powered off, The contents of the file interrupt saved in the data cache are lost. However, the only advantage of saving the file information in the data cache in memory is that the data retransmission table is searched, the retransmission channel is established more quickly, and the data interruption recovery interval is reduced. In another embodiment, software is also provided for performing the technical solutions described in the above embodiments and preferred embodiments. In another embodiment, a storage medium is provided, the software being stored, including but not limited to: an optical disk, a floppy disk, a hard disk, a rewritable memory, and the like. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention. Industrial Applicability According to the above technical solution provided by the present invention, under the DMP protocol, according to the context information of the file to be backed up at the transmission interruption and the first part of the content stored before the transmission interruption, it is determined that the transmission is not successfully transmitted at the interruption of the transmission. The second part of the content, and continue to send the second part of the technical means, to solve the related technology, due to the DMP protocol-based data backup process does not support the breakpoint resume transmission caused by the data backup and recovery interval is too long , Affecting user experience and other technical issues, shortening the time interval for re-backup after data backup is interrupted.

Claims

Claim

1. A data retransmission method for a backup file, comprising:

Receiving a backup request for triggering backup of the backup file by the network data management protocol DMP;

Triggering, according to the backup request, determining, according to the context information of the to-be-backed file at the transmission interruption before the current transmission and the first part of the content stored before the transmission interruption, determining the second part that is not successfully transmitted at the transmission interruption Content, wherein the first part of content and the second part of content constitute the file to be backed up; and at the interruption of the transmission, continuing to transmit the second part of content.

2. The method according to claim 1, wherein before receiving the backup request for triggering the backup of the file to be backed up by using the DMP protocol, the method further includes:

And when the transmission of the file to be backed up is interrupted before the current transmission, the data retransmission entry is established according to the context information and the file description information of the file to be backed up.

The method according to claim 2, wherein, according to the context information of the file to be backed up at the transmission interruption before the current transmission and the first part of the content stored before the transmission interruption, it is determined that the transmission is not successfully transmitted at the interruption of the transmission. The second part of the content, including:

Obtaining file description information of the file to be backed up;

Querying, according to the file description information, whether the file description information of the file to be backed up exists in the data retransmission entry;

If yes, determining the content of the second part according to the association relationship between the context information in the data retransmission entry and the content of the first part.

The method according to claim 2 or 3, wherein the file description information comprises at least one of the following: file size information and file identification information of the file to be backed up.

The method according to claim 4, wherein the file identification information comprises at least one of the following: a file attribute of the file to be backed up, and summary information of the file to be backed up.

6. A data retransmission device for backing up files, comprising: a receiving module, configured to receive a backup request for triggering backup of the backup file by using the network data management protocol DMP; and a determining module, configured to be triggered by the backup request, according to the file to be backed up before the current transmission Context information at the interruption of the transmission and a first portion of the content stored before the interruption of the transmission, determining a second portion of the content that was not successfully transmitted at the interruption of the transmission, wherein the first portion of content and the second portion of content constitute the to-be-backed file;

And a transmission module, configured to continue to transmit the second portion of the content at the interruption of the transmission. The device according to claim 6, further comprising: an establishing module, configured to: according to the context information and file description information of the file to be backed up, when the transmission of the file to be backed up is interrupted before the current transmission Create a data retransmission entry. The device according to claim 7, wherein the determining module comprises: an obtaining unit, configured to acquire file description information of the file to be backed up; and a query unit configured to query the data according to the file description information Whether the file description information of the file to be backed up exists in the transfer entry;

And a determining unit, configured to determine the second part content according to the association relationship between the context information in the data retransmission entry and the first part of the content when there is file description information of the file to be backed up. The device according to claim 7 or 8, wherein the establishing module is configured to establish a data weight according to the context information and file description information of the file to be backed up when the file description information includes at least one of the following: The entry size: file size information and file identification information of the file to be backed up. A data retransmission system for backing up files, including:

The backup server is set to initiate a backup request for triggering backup of the file to be backed up by using the NDMP protocol;

a source server, configured to, according to the backup request, determine that the context information of the file to be backed up before the transmission is interrupted and the first part of the content stored before the transmission interruption, determining that the transmission is not successfully transmitted at the interruption And in the file to be backed up, in addition to the second part of the content of the first part of content, and continue to send the second part of content to the destination server; the destination server is configured to receive the second part of content sent by the source server .