Abstract: A system may parse, during a current filesystem check, a sparse file stream comprising a plurality of Update Sequence Numbers (USNs). A system may access a checkpoint USN that is locally stored apart from the sparse file stream and serves as a checkpoint of a prior USN that was accessed during a prior filesystem check. A system may identify a next byte offset for a next USN of a file in the sparse file stream after the checkpoint USN based on the byte offset of the checkpoint USN. A system may update the checkpoint USN with the next USN. A system may identify a file event from the sparse file stream based on the next USN without polling files or directories on the filesystem. A system may pass the file event to a downstream system.

Abstract: Techniques are provided for modifying a read path to process read operations during a storage operation, such as an operation to migrate objects storing data of a volume. The objects are stored across a storage tier and capacity tier of a source object store. As part of migrating the volume to a destination object store, the objects are migrated to the destination cluster. Directly copying the objects involves multiple read operations to the source object store and a write operation at the destination object store. The techniques provided herein improve the efficiency of the migration by initially sending metadata from the source object store to the destination object store for performing backend block copy operations to migrate the volume.

Abstract: The disclosed data storage management system enables data owners to model the costs and attributes of archiving their data and to readily capture and implement one or more resultant archiving plans. Modeling enables data owners to make informed choices about cost profiles before data is actually archived. Archiving plans devised according to these choices are intended to save on data storage costs and provide a compliance-ready data archive in cloud storage repository(ies). Armed with archiving simulations supplied by the illustrative data storage management system, a data owner may control data placement to predict costs, free up primary storage, and move inactive data to less expensive archive storage. Preferably, the disclosed system is implemented as a software-as-a-service (SaaS) solution, and the accompanying archive storage is implemented as a cloud storage service, but the invention is not limited to SaaS or to cloud-based data archives.

Abstract: A dynamic data policy creation process utilizes certain supervised learning processes to classify data criticality for tagged clients to provide dynamic policy definitions and process adhoc (special) backup requests. Such embodiments prevent the need to manually determine criticality and create protection policies whenever a new data object into the system. A data tagger and KNN-based classifier provide an intelligent solution to data protection ecosystems to meet the dynamic request of data objects through a dynamic backup policy creation system and method that uses certain artificial intelligence (AI) and machine learning (ML) based solutions.

Abstract: A data management system (DMS) may use a staggered full snapshot rollout approach to obtain full snapshots of multiple computing objects. The DMS may identify that a quantity of the multiple objects scheduled for full backups by the DMS exceeds a threshold quantity. The DMS may initiate, at a first time, and based on the quantity of objects exceeding the threshold quantity, a first set of full snapshots corresponding to a first subset of objects included in the multiple objects. The DMS may initiate, at a second time subsequent to the first time, a second set of full snapshots corresponding to a second subset of objects included in the multiple objects. The second subset of objects may be different than the first subset of objects. The DMS may continue to obtain full snapshots of respective subsets of the multiple objects until all of the scheduled full snapshots are obtained.

Abstract: Systems and methods include reception of a request to recover data of a first tenant to a point in time, determination of backups of first and second database table shards corresponding to the point in time, and generation of metadata associating a second tenant with the first and second shards and the backups. In response to a request to access the first second shards, it is determined based on the metadata that the first and second shards are not stored in a storage layer and, in response, the first shard is recovered to a first storage node from the backup of the first shard, the second shard is recovered to a second storage node from the backup of the second shard, and identifiers of the first storage node and the second storage node are returned.

Abstract: A conflict resolution component uses data change measure to resolve conflicts when data assets with the same priority tags arrive simultaneously for protection processing. The data change measure quantifies the extent of modifications or updates made to the asset since a last backup. Assets with a higher data change measure are assigned a higher priority and processed ahead of others with the same priority tag. This reprioritization ensures that backup objects with more significant data changes are handled first. Such a system overcomes the issues associated with present methods backup queueing methods including random scheduling of data having the same priority tags or classifications.

Abstract: In general, the technology relates to a method for managing databases, the method includes receiving a database identifier (DID) for a database, generating, using the DID, a unique identifier (UID) for the database, determining, after the generating, that the database is associated with a data protection policy, and permitting backup operations specifying the UID to be serviced by an agent operatively connected to the database.

Abstract: A cross-account data management (CAM) service of a provider network may assign, to a primary account of an organization of a client, permission to manage resource management plans for other accounts of the organization. The CAM service may specify, using the primary account (e.g., by an administrator using the primary account), a resource management plan (e.g., data backup plan) The CAM service may indicate, using the primary account, multiple accounts of the organization that the resource management plan is to be implemented for. The CAM service may cause, based on the permission assigned to the primary account, the resource management plan to be implemented for the different accounts of the organization (e.g., by causing execution of jobs to implement a backup plan).

Abstract: Aspects of present disclosure include devices within a transmission path of streamed content forwarding received data packets of the stream to the next device or “hop” in the path prior to buffering the data packet at the device. In this method, typical buffering of the data stream may therefore occur at the destination device for presentation at a consuming device, while the devices along the transmission path may transmit a received packet before buffering. Further, devices along the path may also buffer the content stream after forwarding to fill subsequent requests for dropped data packets of the content stream. Also, in response to receiving the request for the content stream, a device may first transmit a portion of the contents of the gateway buffer to the requesting device to fill a respective buffer at the receiving device.

Abstract: An illustrative data storage management system uses a control layer that controls information content presented to users and ensures information privacy between diverse tenants and/or resellers who share the system. The system populates a relationship database as transactions roll in (intake processing), and uses information in the relationship database later when processing responses (output processing). The relationship database comprises associations between e.g., a company ID and any number of entities that were created by or on behalf of the company or that are related to the company's service in the system. The control layer parses raw results that are responsive to requests for information and prevents others' information from being included in the responsive message(s). The techniques disclosed herein are not limited to shared systems managed by service providers, and may be implemented in fully owned and operated systems to add security and privacy among diverse users and/or departments.

Abstract: Certain embodiments disclosed herein reduce or eliminate a communication bottleneck at the storage manager by reducing communication with the storage manager while maintaining functionality of an information management system. In some implementations, a client obtains information for enabling a secondary storage job (e.g., a backup or restore) from a storage manager and stores the information (which may be referred to as job metadata) in a local cache. The client may then reuse the job metadata for multiple storage jobs reducing the frequency of communication with the storage manager. When a configuration of the information management system changes, or the availability of resources changes, the storage manager can push updates to the job metadata to the clients. Further, a client can periodically request updated job metadata from the storage manager ensuring that the client does not rely on out-of-date job metadata.

Abstract: Systems and methods described herein can involve for receipt of an addition or modification of a storage device, executing a validation process from one or more managed validation kits according to a remote copy function associated with the storage device, the one or more managed validation kits selected according to one or more feature types associated with the remote copy function; associating the storage device with a corresponding group of storage devices associated with the remote copy function based on information provided by the one or more managed validation kits; and for the association of the storage device with the corresponding group of storage devices and the execution of the validation process being successful, registering the storage device to a storage class associated with the remote copy function.

Abstract: In some examples, a method comprises: receiving a request to read data within a specified range from a backup file storing at least one base snapshot and at least one incremental snapshot; looking up the specified range in range filters from the backup file, the range filters corresponding to snapshots stored in the backup file and each range filter comprising bits indicating whether data exists at respective ranges within the snapshot corresponding to the respective range filter; and in response to the looking up, reading the requested data from the looked-up range in the backup file.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for backing up a data object in blocks. One of the methods includes determining, for a data object of a backup process, whether a size of the data object or an estimated backup time of the data object satisfies a criterion that, when satisfied, indicates that at least two blocks of the data object should be separately fetched from the source system by different workers; determining one or more markers for end points of the at least two blocks using data from a prior backup of the data object; and causing, at least partially concurrently for two or more blocks from the at least two blocks, a respective backup worker to fetch the respective block from a source system using at least one marker from the one or more markers that defines an end of the respective block.

Abstract: A method and a device configured to transmit information related to a device to a first electronic device through a communication module in accordance with a request of the first electronic device; establish a communication connection with a second electronic device based on the information; receive a backup request for data stored in the device from the first electronic device; generate backup data based on the backup request; transmit the generated backup data to the second electronic device; and reset the device based on a device reset request in a case of receiving the device reset request from the second electronic device.

Abstract: A vulnerability tagging process helps prioritize backups of datasets in a network by monitoring events that affect containers in the network. The monitored events are processed by an AI-based event analyzer to characterize each event in terms of a potential for destruction or damage to the data by each event. A vulnerability measure is calculated as the product of the number of occurrences of each event based on the severity associated with each event. Once the events are analyzed and the vulnerability scores are calculated, the scores are tagged on each workload. The vulnerability tags can then be utilized by the backup server to modify protection policies and/or prioritize backup schedules for the container workloads.

Abstract: A set of deployment applications that are configured to deploy a plurality of resources that compose a containerized application onto at least one cluster of a plurality of different clusters is identified. Each cluster includes a plurality of nodes onto which the plurality of resources can be deployed. A set of clusters of the plurality of clusters onto which the plurality of resources have been deployed as a plurality of deployed resources is identified. User interface imagery that includes information that: identifies a set of deployed resources of the plurality of deployed resources of the containerized application; identifies a total number of deployment applications in the set of deployment applications; and identifies a total number of clusters in the set of clusters is generated. The user interface imagery is presented on a display device.

Abstract: A system and method is provided for selecting a backup plan based on sampled metadata. An exemplary method includes sampling metadata of files on a computer during a predetermined time interval and predicting file usage dynamics for a time interval subsequent to the predetermined time interval, based on a combination of the derivative features and the attributes of the metadata, wherein the predicted file usage dynamics indicate how the files will be utilized on the computer during the time interval. The method includes identifying on the computer at least one newly stored file, selecting a backup plan for the at least one newly stored file based on the file usage dynamics, and backing up the at least one newly stored file to a storage server according to the selected backup plan.

Abstract: A system and method is provided for selecting a backup plan based on sampled metadata. An exemplary method includes sampling metadata of files on a computer during a predetermined time interval, wherein the files are backed up to a storage server in accordance with a first backup plan. The method includes predicting file usage dynamics for a time interval subsequent to the predetermined time interval, based on a combination of the derivative features and the attributes of the metadata, and comparing the predicted file usage dynamics for the time interval with file usage dynamics of the predetermined time interval. In response to determining that a difference between the predicted file usage dynamics and the file usage dynamics of the predetermined time interval exceeds a threshold difference, the method includes selecting a second backup plan for the files, and backing up the files to the storage server accordingly.

Abstract: A method for efficient file-based backups and recoveries. The method includes: receiving, to initiate a backup session, a file-system backup instruction identifying a host file-system; obtaining at least one clone logical cluster number (LCN) corresponding to a file managed by the host file-system, and a region LCN corresponding to a file region of the file; based on a determination that the region LCN matches a clone LCN of the at least one clone LCN: querying a cluster-offset tracking data structure using the region LCN to identify a cluster-offset tracking entry including the region LCN and a container offset; writing, as a session metadata record stored in backup session metadata for the backup session, file metadata describing the file and including the container offset; and transmitting, to a backup target, an information tuple including a backup session identifier generated for the backup session, and the backup session metadata.

Abstract: An example method of hypervisor lifecycle management in a virtualized computing system having a cluster of hosts is described. The method includes: obtaining, by remediation software executing in a host of the hosts, a host state document from a distributed key-value store, the host state document defining a desired state of software in the host, the software including a hypervisor; and performing, by the remediation software in coordination with other hosts of the hosts through the distributed key-value store, a lifecycle operation on the software of the host in response to determining that a current state of the software does not match the desired state.

Abstract: A control and/or monitoring system is disclosed. In an embodiment, the system includes a host device on which an application for generating an Ethernet frame for deriving information about an industrial Ethernet network can be run and an industrial Ethernet tunnel device which is adapted to communicate with the host device. The system is configured to inject the Ethernet frame for deriving an information about an industrial Ethernet network and/or about one or more of the industrial Ethernet devices through the industrial Ethernet tunnel device and to receive an answer in an Ethernet frame format in the host device. An industrial Ethernet tunnel device and a method for control and/or monitoring of one or more devices in an industrial Ethernet network are also disclosed.

Abstract: Methods and apparatus to scale in and/or scale out arbitrary resources managed by a cloud automation system are disclosed. An example apparatus includes processor circuitry; and a non-transitory computer readable medium comprising instructions which, when executed, cause the processor circuitry to: in response to an indication to scale a first component of an application to be deployed: determine an execution plan to scale the first component based on a dependency graph corresponding to a dependency within a blueprint specifying a logical topology of the application; perform a custom action to scale the first component, the custom action identified in a scaling parameter associated with the application; and update operation of a second component based on scaling the first component, the second component dependent on the first component, the update to enable the second component to interact with the first component after the scaling.

Abstract: A query specifying a source repository and a target repository is received from a client device. A source index is generated that corresponds to the source repository and represents a snapshot of metadata associated with data contained in the source data repository. The source index is filtered based on filtering criteria specified by the query to obtain a filtered source index. Attributes of data corresponding to the filtered source index are determined as well as data retrieval type parameters. Without initiating a data migration of the data corresponding to the filtered source index from the source repository to the target repository, predicted data migration metrics associated with the data migration are determined and presented to an end user of the client device. The end user is provided with the capability to initiate or forego the data migration based on an evaluation of the predicted data migration metrics.

Abstract: The present invention aims to reduce the amount of backup to be transferred, and reduce the recovery time, in the case of a server device built in a virtual environment. A VM 10 connects a plurality of volumes 21 and 22, starts up software installed on the volume 21 from the volume 21, stores DB data in the volume 22, and acquires snapshots of the volumes 21 and 22 at different intervals for each, thereby backing up the images 31 and 32.

Abstract: A system for identifying and deleting records of hosts includes a local data manager. The local data manager identifies a discovery event associated with the host and a record type of record types, obtains, in response to identifying, all previously discovered records on the host associated with the record type from a host record repository, obtains discovered records associated with the record type and associated with the host, after obtaining all discovered records and previously discovered records, selects a previously discovered record of the previously discovered records, makes a determination that the previously discovered record does not match any discovered records of the discovered records and is not tagged with a soft delete tag or a hard delete tag, and in response to the determination, tags the previously discovered record with a soft delete tag, and notifies a data manager of modifications to the previously discovered records.

Abstract: This disclosure provides system, methods, and media for identifying inadvertent compression or encryption in data streams from a client that land on a deduplication storage system. When one or more such abnormalities are detected, an alert message is generated to alert the administrator of the deduplication storage system so that corrective actions can be taken to prevent undesired consequences. According to an exemplary method, machine learning techniques are used to plot and smoothen global compression ratios and local compression ratios of historical backups from a client over a period of time. Then, a second derivative of each data point on the smoothened curves is taken and compared with a predetermined threshold to detect whether that the slope of the data point exceeds a threshold. A data point whose slope exceeds the threshold can be determined to be a data point corresponding to a backup that includes compression and/encryption.

Abstract: The present disclosure provides for consistent reads in a global database that is replicated to one or more global clones. A state machine is implemented, and executed independently, for each project in each region. Based on the state of a project when a read request is received, the read request will be served by the global database, served by the global clone, or ignored as an invalid request.

Abstract: A query specifying a source repository and a target repository is received from a client device. A source index is generated that corresponds to the source repository and represents a snapshot of metadata associated with data contained in the source data repository. The source index is filtered based on filtering criteria specified by the query to obtain a filtered source index. Attributes of data corresponding to the filtered source index are determined as well as data retrieval type parameters. Without initiating a data migration of the data corresponding to the filtered source index from the source repository to the target repository, predicted data migration metrics associated with the data migration are determined and presented to an end user of the client device. The end user is provided with the capability to initiate or forego the data migration based on an evaluation of the predicted data migration metrics.

Abstract: Systems and method for automated determination of granular object storage service metrics are provided. In one example, metadata regarding a subset of objects stored in one or more shared containers of an object storage service is retrieved. One or more meta properties (e.g., a storage tier with which the object is associated, a size of the object, an object type, a file type, user-defined tags, and a full path of the object, including, for example, information indicative of the application and the tenant) may be obtained for each object of the subset of objects. The subset of objects satisfy a set of one or more criteria involving the metadata and/or the meta properties. A total storage cost and/or a total size of the subset of objects is determined by aggregating a storage cost and/or a size of each object of the subset of objects.

Abstract: A computer-implemented to control access to data on an off-premises storage system. The method includes defining an access policy for a plurality of files in a file system stored in an on-premises storage system. The method further includes registering the access policy with a first off-premises storage system. The method also includes creating a resource-based cloud access policy based on an on-premise access policy. The method includes determining a set of files from the plurality of files to migrate to the off-premises storage. The method also includes obtaining, for the set of files, an access policy as access metadata. The method further includes migrating the set of files and the access metadata to the off-premises storage.

Abstract: Embodiments of the present disclosure relate to a method, an electronic device, and a computer program product for recommending a protection strategy. The method includes obtaining contents of attributes of a plurality of data assets adjusted. The method further includes generating a plurality of vector representations for the plurality of data assets based on the contents of the attributes. The method further includes dividing the plurality of data assets into at least one category based on the plurality of vector representations. The method further includes if it is determined that a protection strategy for one data asset in the at least one category exists, determining the protection strategy as a recommended strategy for another data asset in the at least one category.

Abstract: A method for managing file based backups (FBBs) includes obtaining, by a FBB metadata file manager and by an application, a file request for a file stored in a FBB, wherein the FBB is stored in a backup storage system, identifying, using a FBB metadata file of the FBB, a storage location of the file, initiating generation of a temporary storage device, storing a copy of the file in the temporary storage device using the storage location and the FBB, and initiating, after the storing, access to the copy of the file for the application.

Abstract: An example method of upgrading a distributed storage object from a first version to a second version includes: querying metadata of a first component configured according to the first version of the distributed storage object, the metadata defining extents of data on a disk group of the first component; populating, for a second component configured according to the second version of the distributed storage object, logical and middle maps based on the metadata such that initial entries in the logical map point to initial entries in the middle map, and the initial entries in the middle map point to physical addresses of the disk group of the first component; and reading the data from the disk group of the first component and writing the data to a disk group of the second component while updating the initial entries in the middle map.

Abstract: Aspects of present disclosure include devices within a transmission path of streamed content forwarding received data packets of the stream to the next device or “hop” in the path prior to buffering the data packet at the device. In this method, typical buffering of the data stream may therefore occur at the destination device for presentation at a consuming device, while the devices along the transmission path may transmit a received packet before buffering. Further, devices along the path may also buffer the content stream after forwarding to fill subsequent requests for dropped data packets of the content stream. Also, in response to receiving the request for the content stream, a device may first transmit a portion of the contents of the gateway buffer to the requesting device to fill a respective buffer at the receiving device.

Abstract: An asynchronous first device in communication with an asynchronous second device. The time for the first device to complete a processing cycle is a first device major frame and the first device major frame comprises a first device dedicated processing time slot at the end of the first device major frame. The first device is configured to send a rescheduling signal to the second device when it has completed a first device major frame. The first device is configured, during every first device dedicated processing slot, to: monitor for a rescheduling signal sent from the second device to the first device; and if a rescheduling signal from the second device is received: reschedule the current first device major frame to a rescheduled first device major frame; wherein the end of the rescheduled first device major frame coincides with the time the rescheduling signal from the second device was received.

Abstract: Disclosed are various embodiments for garbage collection for object-based storage systems. A first set of objects stored by an object storage service that have been accessed within a previously defined date range is identified. Then, a second set of objects stored by the object storage service is identified based at least in part on a relationship to one or more objects in the first set of objects. Next, a third set of objects stored by the object storage service that have been created prior to a predefined date is identified. Then, a subset of objects which are members of the third set of objects and not members of the first set of objects or the second set of objects is identified. Finally, a retention action is performed on individual members of the subset of objects based at least in part on a retention policy.

Abstract: A user interface (UI) uses overlays to tag representations of datacenter components with indications of changes that have occurred over a selected time interval. Log files, problem and service reports, and knowledge base items are gathered at various times to generate datacenter snapshots. A pair of snapshots can be compared to detect configuration changes, reported problems and their dispositions, and knowledge-base items introduced during the selected time interval. Trouble-shooting problems can be facilitated by using the interface to find changes that may have led to problems or that may cause problems in the future.

Abstract: An example apparatus comprises at least one memory, instructions in the apparatus, and at least one processor to execute the instructions to identify an agent identifier from a plurality of network command responses, the plurality of network command responses including a plurality of network parameters, apply weighted values to the plurality of network parameters, and determine a total weighted sum of the plurality of network parameters, the total weighted sum corresponding to a connectivity factor of an agent associated with the agent identifier.

Abstract: A distributed agent for backup and restoration of virtual machines collects backup data and meta-data. The distributed agent includes an agent inside a virtual machine and an agent outside the virtual machine. The two kinds of agents communicate with each other to collect data of different types used to backup and restore virtual machines.

Abstract: Systems and methods for deleting backup pieces associated with an application such as a database application. Backup pieces are identified and deleted from the database records and from the backup application.

Abstract: Techniques involve: determining, based on sizes of a storage space used by a file system at a set of historical moments and a current moment, predicted sizes of a storage space to be used by the file system at a plurality of future moments. The techniques further involve: determining sizes of an available storage space and available durations of a set of candidate future moments in the plurality of future moments based on the predicted sizes. The techniques further involve: determining, based on the sizes of the available storage space and the available durations of the set of candidate future moments, predicted values that characterize available storage capacities of the set of candidate future moments. The techniques further involve: determining a target moment from the set of candidate future moments based on the predicted values to recycle at least part of an available storage space of the target moment.

Abstract: Virtualization sprawl can lead to virtual machines with no designated periodic backup. If the data associated with these unprotected virtual machines is not backed up, it cannot be restored if needed, leading to system failures. A data storage system identifies and protects the unprotected virtual machines. For instance, the system compares a list of virtual machines with a list of computing devices having a designated backup policy in the data storage system and determines which of the virtual machines are unprotected. The system further automatically categorizes the unprotected virtual machines, identifies those unprotected virtual machines that remain uncategorized, and applies a default backup policy to the uncategorized and unprotected virtual machines to provide protected virtual machines.

Abstract: In general, the invention relates to a method for backing up data. The method includes receiving a backup instruction from a client device, wherein the backup instruction comprises a backup tag corresponding to a backup operation for a user asset, making a first determination that the backup tag matches a second backup tag specified in a tag file, and in response to the first determination, identifying a checkpoint of a backup associated with the second backup tag, and resuming the backup operation at the checkpoint for the user asset.

Abstract: Disclosed herein are techniques for generating fractional checkpoints on a distributed file system by snapshotting subcomponents referred to as “file sets.” The techniques include capturing a present time; calculating from configured parameters a future wakeup time for a subsequent set of checkpoints from the present time; walking a database of meta file set objects to locate at least one meta file set object; calculating a retention period for a snapshot that is being created; and generating a global data-less snapshot for the meta file set object and remote data file set objects associated with the meta file set object, and then repeating the process for subsequent file set objects in the database.

Abstract: A storage device includes a memory device including a metadata area and a journal data area. A memory controller is configured to control the memory device to write a metadata block to the metadata area and to write a journal data block to the journal data area. The metadata block includes metadata, and the journal data block includes both journal data and metadata storage information. The journal data includes log information pertaining to the metadata, and the metadata storage information includes information pertaining to storage of the metadata block.

Abstract: Some examples relate generally to a data management platform comprising: a storage device configured to store secondary data and one or more processors in communication with the storage device and configured to perform certain operations. The operations may include identifying an aspect of the secondary data stored in the storage device, the secondary data including a backup of respective primary data stored in a primary data source; identifying or receiving an indication of a target to receive data associated with the identified aspect of the secondary data; and transmitting the data associated with the aspect of the secondary data to the target.

Abstract: Methods, systems, and computer storage media for providing log files using logging system operations in a logging system. The logging system operations support memory mapping log files and asynchronously managing file operations. The logging system operations support selectively mapping segments of log files during write operations. The logging operations also support performing file operations (e.g., closing, opening, deleting and serializing files) advantageously as background processes. Selective memory mapping specifically includes incrementally mapping new segments of a log file up to a predetermined log file size limit. The logging operations support processing spare files using spare file memory mapping. A spare file replaces an existing log file to continue writing logging data using the spare file.

Abstract: Methods and systems for backing up and restoring files that have multiple hard links using master file references and index node-based mappings are described. In some cases, file fetching and restoration may be performed by a storage appliance using master file references in which a master file is identified for each multi-link file that is backed-up on the storage appliance and then referenced by one or more hard links to the multi-link file. In other cases, file fetching and restoration may be performed by a storage appliance using index node-based mappings for multi-link files that provide mappings between index node identifiers (e.g., inode numbers) for the multi-link files on a primary system and hard link paths for storing the file contents of the multi-link files on a storage appliance used for backing up the primary system.