In some examples, a system detects recovery, from an unavailable state, of a communication link between a first storage system that includes a first storage volume and a second storage system that includes a second storage volume that is to be a synchronized version of the first storage volume, where while the communication link is in the unavailable state the second storage volume is in an offline state and the first storage volume is in an online state. In response to detecting the recovery of the communication link, the system sends a first tracking metadata for the first storage volume from the first storage system to the second storage system, and in response to receipt of the first tracking metadata at the second storage system that maintains a second tracking metadata for the second storage volume, the system transitions the second storage volume from the offline state to a controlled online state, and initiates a synchronization process to synchronize the second storage volume with the first storage volume.

A server system including a first server to execute first role, other server to execute at other role, spare server and management layer server. The management layer server is configured to allocate first group of users to access first server and other group of users to access other server, receive status information sent by first server and status information sent by other server, analyse status information to determine an operational status of first server and operational status of other server, update role of spare server to first role when operational status of first server indicates failed state and reallocate first group of users to the spare server, and update a role of another spare server to the other role when the operational status of the other server indicates a failed state and reallocate the other group of users to the other spare server.

A memory system includes: a memory device; a first queue suitable for queuing commands received from a host; a second queue suitable for enqueuing the commands from the first queue and dequeuing the commands to the memory device according to the FIFO scheme; and a processor suitable for: delaying enqueuing a read command into the second queue until the program operation is successfully performed when a logical address of a write command, in response to which a program operation is being performed, is the same as a logical address corresponding to the read command enqueued in the first queue; and determining whether or not to enqueue a subsequent read command, which is enqueued in the first queue after the read command, into the second queue.

A server system including a first server to execute first role, other server to execute at other role, spare server and management layer server. The management layer server is configured to allocate first group of users to access first server and other group of users to access other server, receive status information sent by first server and status information sent by other server, analyse status information to determine an operational status of first server and operational status of other server, update role of spare server to first role when operational status of first server indicates failed state and reallocate first group of users to the spare server, and update a role of another spare server to the other role when the operational status of the other server indicates a failed state and reallocate the other group of users to the other spare server.

Staging data on a storage element integrating fast durable storage and bulk durable storage, including: receiving, at a storage element integrating fast durable storage and bulk durable storage, a data storage operation from a host computer; storing data corresponding to the data storage operation within fast durable storage in accordance with a first data resiliency technique; and responsive to detecting a condition for transferring data between fast durable storage and bulk durable storage, transferring the data from fast durable storage to bulk durable storage in accordance with a second data resiliency technique.

Methods, systems, and computer-readable media (transitory or non-transitory) are described herein for automatic backup and replacement of a storage device. According to an example, a storage failure for given storage device may be predicted. A backup process of the give storage device to a remote system may be initiated based on predicting the storage failure for the given storage device. The backup process may create a one-to-one image backup or a user data backup based on a predicted amount of time until the storage failure of the given storage device. A restore process of a new storage device at the remote system may be initiated upon completion of the backup process. The restore process may depend on the backup created during the backup process and/or various types of new storage devices that are available. The new storage device may be based on the given storage device.

In some examples, a system detects recovery, from an unavailable state, of a communication link between a first storage system that includes a first storage volume and a second storage system that includes a second storage volume that is to be a synchronized version of the first storage volume, where while the communication link is in the unavailable state the second storage volume is in an offline state and the first storage volume is in an online state. In response to detecting the recovery of the communication link, the system sends a first tracking metadata for the first storage volume from the first storage system to the second storage system, and in response to receipt of the first tracking metadata at the second storage system that maintains a second tracking metadata for the second storage volume, the system transitions the second storage volume from the offline state to a controlled online state, and initiates a synchronization process to synchronize the second storage volume with the first storage volume.

Methods, computer program products, computer systems, and the like are disclosed that provide for scalable deduplication in an efficient and effective manner. For example, such methods, computer program products, and computer systems can include determining whether a source data store and a replicated data store are unsynchronized and, in response to a determination that the source data store and the replicated data store are unsynchronized, performing a resynchronization operation. The source data stored in the source data store is replicated to replicated data in the replicated data store. The resynchronization operation resynchronizes the source data and the replicated data.

A high frequency snapshot technique improves data replication in a disaster recovery (DR) environment. A base snapshot is generated from failover data at a primary site and replicated to a placeholder file at a secondary site. Upon commencement of the base snapshot generation and replication, incremental light weight snapshots (LWSs) of the failover data are captured and replicated to the secondary site. A staging file at the secondary site accumulates the replicated LWSs (“high-frequency snapshots”). The staging file is populated with the LWSs in parallel with the replication of the base snapshot at the placeholder file. At a subsequent predetermined time interval, the accumulated LWSs are synthesized to capture a “checkpoint” snapshot by applying and pruning the accumulated LWSs at the staging file. Once the base snapshot is fully replicated, the pruned LWSs are merged to the base snapshot to synchronize the replicated failover data.

A distributed storage management system comprising nodes that form a cluster, a distributed block layer that spans the nodes in the cluster, and file system instances deployed on the nodes. Each file system instance comprises a data management subsystem and a storage management subsystem disaggregated from the data management subsystem. The storage management subsystem comprises a node block store that forms a portion of the distributed block layer and a storage manager that manages a key-value store and virtualized storage supporting the node block store. A file system volume hosted by the data management subsystem maps to a logical block device hosted by the virtualized storage in the storage management subsystem. The key-value store includes, for a data block of the logical block device, a key that comprises a block identifier for the logical block device and a value that comprises the data block.