A data center for data backup and replication, including a pool of multiple storage units for storing a journal of I/O write commands issued at respective times, wherein the journal spans a history window of a pre-specified time length, and a journal manager for dynamically allocating more storage units for storing the journal as the journal size increases, and for dynamically releasing storage units as the journal size decreases.

A method for primary-backup server switching. A control server monitors whether a primary server fails. The control server is in communication connection with the primary server and a backup server. The primary server is provided with a primary memory database. The primary memory database is configured to save in real time state information of the primary server each time after an operation is executed, and the state information is read and saved in real time by a backup memory database in a backup server. In response to a failure of the primary server, the control server sends a primary-backup switching command to the backup server. The primary-backup switching command is configured to instruct the backup server to upgrade itself to become a new primary server according to the state information saved in the backup memory database.

A fault tolerant server according to the present invention configured to duplicate information processing by an online subsystem and an offline subsystem, the fault tolerant server operates to: execute entire copy processing for copying all data being stored in the memory of the online subsystem into the memory of the offline subsystem without stopping execution of information processing by the processor of the online subsystem, before start of duplication; detect data, the data satisfying a criterion indicating that content of data is changed during the entire copy processing, among data being stored in the memory of the online subsystem; and copy the detected data from the memory of the online subsystem into the memory of the offline subsystem.

The present disclosure relates to an automatic switching method and an automatic switching system. The automatic switching method includes: an automatic switching device monitoring in real time a service state of an operation server; when the automatic switching device monitors that the operation server has terminated providing service for a client terminal, the automatic switching device sending to the operation server a switching instruction for switching a current configuration of the operation server and sending to a backup server a notification message for switching a current configuration of the backup server; and the backup server switching the current configuration of the backup server to a preset first configuration according to the notification message, and providing service for the client terminal; wherein the first configuration is the configuration of the operation server when the operation server provided service.

A method of managing databases (DBs) in duplex servers includes: updating a DB in the backup server to a first version; transmitting a list of name keys in the backup server to the active server; transmitting name keys that are identical between the active server and the backup server to the backup server; and synchronizing DBs between the active server and the backup server by using the identical name keys. The data can be synchronized between DBs having different versions based on name keys.

A redundancy device which is configured to communicate with a redundancy opposite device and perform a redundancy execution, the redundancy device includes receivers configured to receive individually HB signals transmitted from the redundancy opposite device, a calculator configured to calculate a number of normal communication paths among communication paths of the HB signals based on a reception result of the receivers, a comparator configured to compare a calculation result of the calculator with a predetermined threshold value, and a changer configured to change the redundancy device from a standby state to an operating state, or change the redundancy device from the standby state to a not-standby state in which the redundancy execution is released, based on the calculation result of the calculator and a comparison result of the comparator.

A method and system for checkpointing at least one application in an application group. At least one full checkpoint and at least one incremental checkpoint are created for the application in the application group. The at least one incremental application checkpoint is merged against the at least one full application checkpoint, and checkpointing across all applications in the application group is synchronized. A storage checkpoint is taken for at least one of the full checkpoint and the incremental checkpoint, and memory and storage checkpoints are synchronized and consistent.

According to one aspect of the present invention, there is provided a method for performing storage control. Member storage media and a hot spare storage medium are identified in a storage system. The member storage media are members of a storage medium array, and the hot spare storage medium is for joining in the storage medium array when a member storage medium fails. Data on a member storage medium having a write amplification effect is migrated to the hot spare storage medium. In the member storage medium having a write amplification effect, an erase operation is performed on a storage medium where the migrated data is located. Embodiments of the present invention can alleviate adverse impact caused by a write amplification effect.

A daisy-chain storage synchronization (DSS) system and method that permits a daisy-chain of interconnected pass-thru disk drive controllers (PTDDCs) each connected to a SATA local disk drive (LDD) disk storage element (DSE) to support state synchronization within PTDDCs in the daisy-chain is disclosed. The PTDDCs within the daisy-chain are configured to individually maintain drive state information (DSI) relating to the LDD as well as chain state information (CSI) relating to the individual PTDDCs within the daisy-chain. This state information may be modified on receipt of out-of-band signaling (OBS) from other PTDDC elements up the daisy-chain as well as OBS from other PTDDC elements down the daisy-chain, CSI is determined in part by conventional SATA OBS state register protocols that are modified by internal state registers (ISR) in each individual PTDDC daisy-chain element so as to make the DSS transparent to existing SATA OBS single-disk standard hardware command protocols.

Embodiments of the invention relate to recovering from a disaster associated with an information technology environment. An information technology environment is replicated to a service provider. A recovery plan is generated for the environment. The recovery plan includes two processes. In response to the service provider receiving a disaster recovery request associated with the environment, the service provider executes a disaster recovery protocol. The protocol includes simultaneously executes the first and second processes. The first process operates a workload in the form of one or more containers, and the second process is a background process that creates a replica of the environment. After completion of the replica creation, the workload is migrated to the replica.