Abstract: An interface between an existing local file system and a data store generates and exports to the data store a versioned file system. The state of the local file system at a given point in time can be determined using the versioned file system. In operation, the interface creates and exports to the data store structured data representations, which correspond to versions of the local file system, as well as actual file system data that these structured data representations represent. A cache associated with the interface stores recently used data and metadata, as well as all write data and metadata waiting to be transferred to the data store. Prior to transfer, one or more data transformations may be applied to the data and metadata. In one embodiment, the data store comprises one or more cloud storage service providers. A content control system is used to configure and manage the interface.

Abstract: This disclosure is directed to a computing system that performs techniques relating to the secure storage, maintenance, and retrieval of data. Techniques described in this disclosure may prevent, limit, or otherwise insulate the data from unauthorized access by hackers, rogue devices, and unauthorized users. In some examples, a computing system may store a file by fracturing the file into multiple data blocks, encrypting the data blocks or the data stored within the data blocks, and storing the data blocks in scattered locations on a network. Further, the computing system may occasionally move at least some of the stored data blocks, and may, upon moving such data blocks, reencrypt the moved data blocks with a different encryption key. Still further, the computing system may inject fake data and/or fake data blocks into the system.

Abstract: A storage system that can achieve a cryptographic operation circuit that supports multiple types of cryptographic operation formats. The cryptographic operation circuit is provided that encrypts data according to the format determined by the processor based on a request by the host terminal for writing the data into the storage device, and decrypts the encrypted data on the data stored in the storage device according to the format determined by the processor based on a request by the host terminal for reading the data from the storage device.

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: Techniques involve: acquiring a first source snapshot for a source storage object stored in a source storage device; determining first difference data between the first source snapshot and the source storage object or a second source snapshot for the source storage object, creation time of the first source snapshot being associated with creation time of the second source snapshot; and sending the first difference data to a destination storage device to enable the destination storage device to create a first destination snapshot for a destination storage object stored in the destination storage device based on the first difference data. Such techniques can migrate snapshots more efficiently to improve storage management efficiency.

Abstract: An improved information management system that implements a staging area or cache to temporarily store primary data in a native format before the primary data is converted into secondary copies in a secondary format is described herein. For example, the improved information management system can include various media agents that each include one or more high speed drives. When a client computing device provides primary data for conversion into secondary copies, the primary data can initially be stored in the native format in the high speed drive(s). If the client computing device then submits a request for the primary data, the media agent can simply retrieve the primary data from the high speed drive(s) and transmit the primary data to the client computing device. Because the primary data is already in the native format, no conversion operations are performed by the media agent, thereby reducing the restore delay.

Abstract: Novel tools and techniques are provided for implementing virtual machine (“VM”) management, and, more particularly, to methods, systems, and apparatuses for implementing VM management using hardware compression. In various embodiments, a computing system might identify one or more first virtual machines (“VM's”) among a plurality of VM's that are determined to be currently inactive and might identify one or more second VM's among the plurality of VM's that are determined to be currently active. The computing system might compress a virtual hard drive associated with each of the identified one or more first VM's that are determined to be currently inactive. The computing system might also perform or continue to perform one or more operations using each of the identified one or more second VM's that are determined to be currently active.

Abstract: A technique replicates an index of an operations log (oplog) from a primary node to a secondary node of a cluster in the event of failure. The oplog functions as a staging area to coalesce random write operations directed to a virtual disk (vdisk) stored on a backend storage tier. The oplog temporarily caches write data as well as metadata describing the write data. The metadata includes descriptors to the write data corresponding to offset ranges of the vdisk and are used to identify ranges of write data for the vdisk that are cached in the oplog. To facilitate fast lookup operations of whether write data is cached in the oplog, an oplog index provides a state of the latest data for offset ranges of the vdisk that enables fast failover of metadata used to construct the oplog index in memory without downtime or significant metadata replay.

Abstract: Embodiments of the present disclosure provide a data storage method, an electronic device, and a computer program product. The method includes: determining the number of at least one first storage apparatus of a storage system, each first storage apparatus being persistent and storing a log that includes record entries of to-be-stored data; and writing, if it is determined that the number is greater than a threshold number, the to-be-stored data into a corresponding memory table from the log where the to-be-stored data is located, wherein data in the memory table will be written to a second storage apparatus of the storage system. In this way, the storage efficiency of the storage system can be improved.

Abstract: In some embodiments, a method for cluster resource scheduling, includes determining at least one load score; determining a memory score; determining an IO score; and monitoring a message bus for candidate messages when each of the at least one load score, memory score, and IO score is less than a pre-determined health threshold. In some embodiments, a host computer system for hosting a plurality of virtual machines (VMs), includes: a memory; a network adapter for communicating with the cluster by way of a message bus; a processor in electronic communication with the memory and the network adapter, wherein the processor is programmed to: determine at least one load score; determine a memory score; determine an IO score; and monitor the message bus for candidate messages when each of the at least one load score, memory score, and IO score is less than a pre-determined health threshold.

Abstract: Aspects of the present disclosure relate to managing concurrent updates on data. A transactional update on at least one record within a data set is detected. A log is generated for the transactional update, the log including an image of the at least one record within the data set before the transactional update. A batch update is detected. A determination is made whether the batch update collides with the transactional update by referencing the log. In response to determining that the batch update collides with the transactional update, a collision policy is referenced. A collision action indicated in the collision policy is then issued.

Abstract: A processing device, operatively coupled with a memory device, is configured to perform a write operation on a page of a plurality of pages of a data unit of a memory device, to store host data in the page of the data unit. The processing device further generates a parity page for the host data stored in the page of the data unit and adds the parity page to parity data stored at a parity data storage location. Responsive to determining that a first size of the stored parity data satisfies a first condition, the processing device initiates execution of a compression algorithm to compress the stored parity data. Responsive to determining that a second size of the parity data resulting from the execution of the compression algorithm satisfies a second condition, the processing device performs a scan operation to release at least a subset of the stored parity data.

Abstract: A method and system for cache-based flow of a simple copy command is disclosed. The present disclosure generally relates to methods and systems for executing a simple copy command in a manner that mitigates additional latency in the device. According to certain embodiments, a copy command manager that includes one or more copy command slots is provided. When a simple copy command is received from a host, a copy command slot is allocated to the command, and the simple copy command is copied into the copy command slot. Upon copying the simple copy command to the copy command slot, an overlap table of the data storage device controller is updated to indicate the copy has been completed, and the completion is posted to the host. After posting, the simple copy command is carried out in the background through completion.

Abstract: Creating a replica of a storage system, including: receiving, by a first storage system from a computing device, data to be stored on the first storage system; reducing, by the first storage system, the data using one or more data reduction techniques; sending, from the first storage system to the second storage system, the reduced data, wherein the reduced data is encrypted; and sending, from the second storage system to a third storage system, the reduced data, wherein the reduced data is encrypted.

Abstract: Technologies are disclosed for monitoring network traffic using traffic mirroring. According to some examples, traffic mirroring allows customers to monitor traffic at different sources within a VPC. For example, a source may be any Elastic Network Interface (ENI) in their VPC, including elastic network interfaces (ENIs) on virtual machine instances, Network Address Translation (NAT) Gateways, Load Balancers, VPC endpoints, Internal Gateways, Transit Gateways, and more. Filters can be utilized to determine the network traffic to mirror. A customer may also configure to monitor real-time traffic with a monitoring appliance of their choice. With traffic mirroring, data traffic may be identified and sent to one or more target devices. Customers may monitor traffic within a VPC for content inspection, forensic analysis, troubleshooting, record keeping, and the like.

Abstract: Data storage management may include configuring a stretched volume in a metro cluster configuration using a first volume and a second volume both configured as a same logical volume, L1; receiving I/O operations at the metro cluster configuration directed to L1, wherein the I/O operations include a write operations that are received at a first system of the metro cluster configuration and that write first data to the first volume; viewing values of a metric regarding data replication performed for the first volume to replicate data between systems of the metro cluster configuration for writes directed to the first volume; responsive to said viewing, determining whether the first metric values denote a problem has occurred in the metro cluster configuration at a first point in time; and responsive to determining that the problem has occurred at the first point in time, performing one or more corrective actions.

Abstract: Techniques and mechanisms described herein facilitate the execution of a software program container having a plurality of layers. Each layer may include a plurality of files. For instance, a base layer may include a version of an operating system, while an upper layer may include a software program configured to run within the operating system. Different layers may store, create, or modify the same file. However, the precedence of the version of the data for the file may be based on an ordering of the layers. For example, the version of the file in a higher layer should supersede the version of the file in a lower layer. In some implementations, a privileged storage container that runs atop a virtualization layer may manage storage resources for other containers. The privileged storage container may store each file in a software program container as a snapshotable object.

Abstract: A control method is applied to a flash memory controller, which includes the following steps: creating a write time table, wherein the write time table records block numbers of blocks having data stored therein and corresponding first time and second time; referring to the write time table to determine whether there is at least one first block in the flash memory module whose first time is earlier than a first threshold, and if so, recording the at least one first block into an expired block table; referring to the write time table to determine whether there is at least one second block in the flash memory module whose second time is earlier than a second threshold, and if so, recording the at least one second block into the expired block table; and referring to the expired block table to perform an expired block recycling operation.

Abstract: A backup manager for providing backup services includes storage and a backup orchestrator. The persistent storage stores prediction models. The backup orchestrator obtains a computing resource availability for a client; generates a prediction model of the prediction models using the computing resource availability for the client; predicts, using the prediction model and live data, a future computing resource availability for the client; and initiates generation of a backup for the client at an unscheduled time that is based, at least in part, on the future computing resource availability.

Abstract: A remote data replication method and a storage system, where a production array sends a data replication request to a disaster recovery array. The data replication request includes an identifier of a source object and a data block corresponding to the source object. The data block is stored in physical space of a hard disk of the production array. The disaster recovery array receives the data replication request. The disaster recovery array creates a target object when the disaster recovery array does not include an object having a same identifier as the source object. An identifier of the target object is the same as the identifier of the source object, the disaster recovery array writes the data block into the physical space.

Abstract: The present disclosure relates to a method, device and computer program product for managing a backup job. Specifically, there is provided a method for managing a backup job, the backup job being used to store a data object to a storage system. In the method, the difference between the data object specified by the backup job and a copy of the data object in the storage system is determined. In response to determining the difference meets a predetermined threshold, a difference area in the data object where there might exist the difference is determined. With respect to a first block within the difference area, in a group of blocks in the data object, the backup job is processed based on a first query result from the storage system, the first query result indicating whether data in the first block differs from data in a corresponding block in the copy.

Abstract: An example operation may include one or more of retrieving a snapshot of key values of a world state database, retrieving a hash of the snapshot from a blockchain associated with the world state database, determining whether the snapshot is valid based on the hash of the snapshot retrieved from the blockchain, and in response to determining the snapshot is valid, updating key values of a world state database based on the snapshot of key values.

Abstract: A method, system and devices for backing up data on a mobile device connected to a host computer is disclosed. The method comprises: displaying a web page of a web-based device management application in an Internet browser on the host computer, the web page including an interface element for inputting a request to backup data on the mobile device; receiving, via the interface element, the request to backup data on the mobile device; and in response to receiving the request to backup data on the mobile device: obtaining, at the host computer, first data from the mobile device; and storing the first data.

Abstract: A method, system and computer-usable medium which provides a format in which data is written to a dump data set to allow use of Fast Replication technology for both backing up and restoring of both datasets and volumes. Such a format allows any data that can be captured at a track level to be written to the dump data set via Fast Replication. When using this methodology of backing up and restoring, backups should be made to devices that support Fast Replication technology and restoration of the data should be to devices which are capable of being the target of a Fast Replication for that backup device.

Abstract: In one aspect, a redundant array of independent disk (RAID) memory storage system includes a plurality of data storage disks comprising data blocks, a first redundancy storage disk comprising parity blocks that are a parity by row of the data blocks in the data storage disks, a second redundancy storage disk comprising parity blocks storing parities of diagonals of the data blocks in the data storage disks, a third redundancy storage disk comprising parity blocks storing parities of diagonals of the data blocks in the data storage disks and circuitry configured to recover data from three failed storage disks.

Abstract: Improved data management systems for managing and maintaining unstructured data in a computing system environment. Data content is associated with particular types of metadata to create data objects. In certain examples, the metadata is stored in various fields of the data objects, certain fields being designated as permanently read-only after their creation. Such fields can include, for instance, a unique identifier, a type of content and a classification governing copy permissions relating to the data object. Data objects, or didgets, can be grouped into logical containers referred to as chambers, which are further grouped by common control elements or attributes into domains. Chambers within a particular domain can generally freely share information therebetween, including copies of various types of didgets. A control program, or didget manager, in each domain manages the creation of didgets and subsequent operations directed thereto.

Abstract: Systems and methods for copy on write storage conservation are presented. In one embodiment a copy on write storage conservation method includes creating and mounting a snapshot; mounting a snapshot; monitoring interest in the snapshot; initiating a copy on write discard process before a backup or replication is complete; and deleting the snapshot when the backup or replication is complete. In one embodiment the method also includes marking a file as do not copy on write. In one embodiment, the copy on write discard process includes discarding copy on write data when a corresponding read on the file in the snapshot is successful. Initiating a copy on write discard process can be done at a variety of levels (e.g., a file level, an extent level, a block-level, etc.).

Abstract: A method is provided for restoring data from a backup storage volume onto a source storage volume. A content of a memory unit of the backup storage volume and a content of the corresponding memory unit of the source storage volume are loaded into a computer memory, and are compared in the computer memory for identity. The content of the memory unit of the backup storage volume is written to the corresponding memory unit of the source storage volume if the comparison indicates that the content of the compared memory units is not identical. The invention further relates to a system for restoring data from a backup storage volume onto a source storage volume comprising a restore software running on a data processing device, which is connected to the backup storage volume and the source storage volume, whereby the restore software performs the above method.

Abstract: A storage system including first storage devices constituting a first logical storage area, second storage devices constituting a second logical storage area; and a storage control apparatus. The storage control apparatus manages the first and second logical storage areas so that the data stored in the first and second logical storage areas have redundancy, and parity data for the data stored in the second logical storage area are stored in parity storage areas arranged in part of the second storage devices. When part of the first storage devices constituting part of the first logical storage area fail, the storage control apparatus generates part of the data stored, before the failure, in the part of the first storage devices, and stores the generated part of the data in at least part of the second parity storage areas in the second logical storage area.

Abstract: A mechanism is provided for adding point-in-time copy relationships to a data processing system. A request is received to establish a first point-in-time copy relationship. Responsive to determining that a first target of the first point-in-time copy relationship is target write inhibited, that a source of the first point-in-time copy relationship is a source of a first continuous synchronous copy relationship, that a target of the first continuous synchronous copy relationship is part of a second point-in-time copy relationship, and that the source of the first point-in-time copy relationship is part of a volume swap configuration, a volume swap relationship is added between the first point-in-time target volume and the second point-in-time target volume to the volume swap configuration.

Abstract: A method and system for manipulating a spin state of each disk in a drive array is disclosed. In one embodiment, a method includes monitoring input/output (I/O) requests to each disk drive in a disk array and identifying any disk drive as an inactive disk drive based on a number of I/O requests directed to said any disk drive for a given time interval. The method further includes moving data from the inactive disk drive to an active disk drive having a free disk space to store the data and updating metadata associated with the data using a log-structured file system for the disk array. Further, the method includes manipulating a spin state of the inactive disk drive by spinning down the inactive disk drive to conserve power. Furthermore, the method includes redirecting subsequent I/O requests for the inactive disk drive to the active disk drive by accessing the metadata of the log-structured file system.

Abstract: A judgment apparatus includes a processor that executes a procedure, the procedure including obtaining a plurality of pieces of data having a certain relationship with a specific number or more of pieces of data included in a first data group, in the case that a piece of data included in a second data group different from the first data group does not have the certain relationship with the specific number or more of pieces of data included in the second data group, judging whether the piece of data has the certain relationship with the specific number or more of pieces of data included in the obtained plurality of pieces of data, and storing the piece of data in a storage device in the case that the piece of data is judged to have the given relationship with the specific number or more pieces of data.

Abstract: A redundant array of independent disk (RAID) memory storage system comprising data storage blocks arranged in a first plurality of data rows and a second plurality of data columns, wherein parity data is stored in additionally defined parity blocks, and wherein numbers of data blocks in respective columns are different, to accommodate the additional diagonal parity data block that the geometry of the system requires. The system is suitable for an SSD array in which sequential disk readout is not required.

Abstract: An apparatus comprising an array controller and a cache. The array controller may be configured to read/write data to a first array of drives of a first drive type in response to one or more input/output requests. The cache may be configured to (i) receive said input/output requests from the array controller, (ii) temporarily store the input/output requests, and (iii) read/write data to a second array of drives of a second drive type in response to the input/output requests. The first array of drives may be configured to copy the data directly to/from the second array of drives during a cache miss condition such that the array controller retrieves the data stored in the first array of drives through the second array of drives without writing the data to the cache.

Abstract: Various mechanisms are disclosed herein for the saving and restoring of virtual machine environment state. For example, virtual machine state can be either be saved or (multiple) snapshots can be taken of the virtual machine state. In the latter case, virtual processors can be allowed to run while the memory of the virtual machine state is being saved. In either case, virtual devices associated with the virtual machine environment can be quiesced such that these devices can prepare themselves to be saved. Once such virtual devices and memory are saved, they can also be restored. For example, restoration of memory can occur while virtual processors are running at the same time. And, moreover, restoration can occur in batches of pages, thus optimizing the response time for restoring saved data.

Abstract: A device with an interconnect having a plurality of memory controllers for connecting the plurality of memory controllers. Each memory controller of the plurality of memory controllers is coupled to an allocated memory for storing data. Further, each memory controller of the plurality of memory controllers has one accelerator of a plurality of accelerators for mutually exchanging data over the interconnect.

Abstract: Embodiments described herein are directed to providing scalability to software applications. A computer system partitions a portion of data stored in a directory services system into multiple different data partitions. Each data partition includes a primary writable copy and at least one secondary read-only copy of the data. The computer system receives a client request for a portion of the data that is stored in the directory services system and accesses various stored partition mappings to determine which of the different data partitions includes the requested data. The computer system also accesses a dynamic copy locator to determine which of the read-only copies of the indicated partition to access and provide the accessed primary writeable copy of the indicated partition and the determined read-only copy to the client in a virtualized manner so that the client is not aware of the data partitions.

Abstract: Migrating data may include determining to copy a first data block in a first memory location to a second memory location and determining to copy a second data block in the first memory location to the second memory location based on a migration policy.

Abstract: A system and method for using a snapshot as a data source is described. In some cases, the system stores a snapshot and an associated data structure or index to storage media to create a secondary copy of a volume of data. In some cases, the associated index includes application specific data about a file system or other application that created the data to identify the location of the data. The associated index may include three entries, and may be used to facilitate the recovery of data via the snapshot.

Abstract: A RAID bad block module is added to a RAID controller. The bad block module intercepts bad block errors and marks them in a bad block table. When a bad block error is intercepted the bad block module logs the error and determines, based on the error and previously received errors logged in the table, whether the RAID controller can handle the error without failing the entire array. If so, the bad block module passes the error to the RAID controller. Else, the bad block module passes the error to an application or operating system where it is handled like any other disk error. Thus, instead of failing the entire array, the bad block errors are dealt with by the operating system.

Abstract: Improved data management systems for managing and maintaining unstructured data in a computing system environment. Data content is associated with particular types of metadata to create data objects. In certain examples, the metadata is stored in various fields of the data objects, certain fields being designated as permanently read-only after their creation. Such fields can include, for instance, a unique identifier, a type of content and a classification governing copy permissions relating to the data object. Data objects, or didgets, can be grouped into logical containers referred to as chambers, which are further grouped by common control elements or attributes into domains. Chambers within a particular domain can generally freely share information therebetween, including copies of various types of didgets. A control program, or didget manager, in each domain manages the creation of didgets and subsequent operations directed thereto.

Abstract: A method may comprise receiving a page of data to be stored on a storage resource. The method may also comprise determining, for each particular inversion mode of a plurality of inversion modes, the number of bits of the page of data to be inverted to store a representation of the page of data in accordance with the particular inversion mode. The method may additionally comprise determining a selected inversion mode from the plurality of inversion modes for the page of data, the selected inversion mode comprising the inversion mode for which the least number of physical bit transitions are required to store the representation of the page of data in accordance with the selected inversion mode. The method may further comprise storing the representation of the page of data in a data memory in accordance with the inversion mode.

Abstract: A mechanism is provided for automatic use of large pages. An operating system loader performs aggressive contiguous allocation followed by demand paging of small pages into a best-effort contiguous and naturally aligned physical address range sized for a large page. The operating system detects when the large page is fully populated and switches the mapping to use large pages. If the operating system runs low on memory, the operating system can free portions and degrade gracefully.

Abstract: A first storage system copies data of a virtual area of a first virtual volume to a virtual area of a second virtual volume of a second storage system, monitors accesses with respect to multiple virtual areas of the first virtual volume, updates access information related to the accesses of the multiple virtual areas, and, based on the access information, reallocates data inside an actual area of a first pool allocated to the virtual area of the first virtual volume. The first storage system sends the access information to the second storage system. The second storage system receives the access information, and, based on the access information, reallocates data inside the actual area allocated to a virtual area of the second virtual volume.

Abstract: It is an object to use a storage region in an efficient manner and maintain a performance of a storage system. A volume group GR11 includes reference volumes 1411, 1413, and 1415 and source volumes 1412, 1414, 1416, and 1417 that derive from the reference volumes. Each of the volumes stores only the difference data from a volume that is a parent thereof. A volume that is a cause of a problem is moved or copied from a pool of the moment 1410 to other pool 1420. A configuration of a volume group is modified.

Abstract: In one aspect, a method includes obtaining data on components of a virtualization server comprising acquiring a mapping of virtual disks in a virtual store to storage disks, obtaining data on components of a storage array comprising acquiring a mapping of logical units in the storage array to the storage disks, the logical units replicating data from a corresponding storage disk, correlating each virtual disk to a logical unit based on the mapping of the virtual disks to the storage disks and the mapping of the logical units to the storage disks, retrieving replication data of the logical units from the storage arrays and, for a selected virtual store, checking that the selected virtual store has a replica for all the required storage disks mapped to the virtual disks of the selected virtual store.

Abstract: Methods and software are provided for “hot migration” of data an original storage unit for a target system to destination storage unit. In one embodiment, a virtual storage device is provided, having a control block mapped to both the original storage unit, as well as to the destination storage unit. The target system is stopped, the virtual storage device is substituted for the original storage unit, and the target system is restarted. The virtual storage device directs requests to the destination storage unit, and fulfills read requests from whichever of the two storage units has a valid copy of data requested (depending, e.g., on whether the data is as yet unchanged, has been re-written, or has been copied, during the migration process). Unchanged data blocks are copies from the original storage unit to the destination storage unit. The target system is stopped, the virtual storage device is disconnected from the target system, and the destination storage unit is connected in its place.

Abstract: A storage system includes a first storage apparatus including a first logical volume and a second storage apparatus including a second logical volume. The first and second logical volumes are set as a High Availability pair and associated with a virtual volume. When receiving a write request to the virtual volume, the storage system manages storage area in the first logical volume regarding to the write request as storage area during data duplication, writes data in duplicate, in order from the first logical volume to the second logical volume. When receiving a read request to the virtual volume, the first storage apparatus waits for completion of the data duplication and reads data from the first logical volume if the storage area is during the data duplication, and the first storage apparatus reads data from the first logical volume if the storage area is not during the data duplication.

Abstract: A method for resilvering a storage pool includes determining whether any of a first plurality of blocks in the storage pool, comprising metadata, require resilvering, determining whether any of a second plurality of blocks in the storage pool, comprising data, require resilvering, resilvering all of the first plurality of blocks that require resilvering, and resilvering all of the second plurality of blocks that require resilvering, wherein all of the first plurality of blocks that require resilvering are resilvered prior to resilvering any of the second plurality of blocks.

Abstract: Storage systems with reduced energy consumption, methods of operating thereof, corresponding computer program products and corresponding program storage devices. Some non-limiting examples of a write method include: configuring a plurality of storage disk units such that at any given point in time there are at least two storage disk drives operating in active state in any storage disk unit; caching in a cache memory one or more write requests and generating a consolidated write request corresponding to a stripe in a RAID group; destaging the consolidated write request; and writing the destaged consolidated write request in a write out of place manner to one or more storage disk drives operating at the destage point of time in active state.