Abstract: Described herein are systems and methods for performing TRIM commands in a data storage system. An example data storage system can include physical storage including a solid state drive (SSD), and a storage system computer operably coupled to the physical storage. The storage system computer can include a processing unit and a memory operably coupled to the processing unit. The data storage system can further include a distributed volume management (DVM) module stored in the memory that, when executed by the processing unit, causes the processing unit to: allocate a logical volume from the physical storage; subdivide the logical volume into a plurality of logical blocks; maintain a mapping table for tracking the logical blocks of the logical volume; and in response to a predetermined event, execute a TRIM command for one or more unused data blocks of the SSD.

Abstract: Systems, methods, and computer-readable media for handling I/O operations in a storage system are described herein. An example method includes assigning each of a plurality of storage devices to one of a plurality of tiers; imposing a hierarchy on the tiers; creating a logical volume by reserving a portion of a storage capacity for the logical volume without allocating the portion of the storage capacity to the logical volume; and assigning the logical volume to one of a plurality of volume priority categories. The method includes receiving a write I/O operation directed to a logical unit of the logical volume; and allocating physical storage space for the logical unit of the logical volume in response to the write I/O operation. The physical storage space is located in one or more storage devices. The method includes writing data associated with the write I/O operation to the one or more storage devices.

Abstract: Systems and methods for handling input/output operations during a space crunch are described herein. An example method includes striping a volume across a plurality of storage nodes, and maintaining a cluster volume table (CVT) storing information regarding distribution of the logical blocks. Additionally, the CVT includes a plurality of entries, where each of the entries includes information identifying a respective owner storage node of a respective logical block. The method also includes receiving a write I/O operation directed to an unallocated logical block owned by a landing storage node, where the landing storage node lacks free storage capacity, and locking the unallocated logical block. The method further includes updating the CVT to identify a storage node having free storage capacity as owner storage node of the unallocated logical block, and unlocking the unallocated logical block, wherein the write I/O operation proceeds at the storage node having free storage capacity.

Abstract: Systems and methods for consolidating space in a storage cluster are described herein. An example method can include striping a volume across a plurality of storage nodes, and maintaining a cluster volume table (CVT) storing information regarding distribution of a plurality of logical blocks across the storage nodes. The CVT can include a plurality of entries, where each of the entries can include information identifying a respective owner storage node of a respective logical block. The method can also include adding a new storage node to the storage cluster, and transferring data for one or more logical blocks from each of the storage nodes to the new storage node based on respective usage ratios of the storage nodes. The method can further include updating the CVT to identify the new storage node as owner storage node of the one or more logical blocks transferred to the new storage node.

Abstract: An example computer-implemented method for performing failover operations in a data storage system is described herein. The data storage system can include a first storage controller and a second storage controller for processing input/output (“I/O”) operations for the data storage system. The method can include, in response to a failure of the first storage controller, performing failover operations with the second storage controller, and processing the I/O operations with the second storage controller. The failover operations can include preparing a disk subsystem layer for I/O operations, preparing a device manager layer for the I/O operations, and preparing a network layer for the I/O operations. The disk subsystem, device manager, and network layers can be prepared for the I/O operations without dependencies. In particular, preparation of the network layer is not dependent on preparation of the disk subsystem layer or the device manager layer.

Abstract: Technologies are described herein for providing file-level CDP of files stored on a remote storage system. A client module executing on a client computer monitors for modifications made at the client computer to files or folders stored on a virtual storage volume provided by the remote storage system. Upon detecting a modification of a monitored file, the client module sends a message to the remote storage system identifying the file. A server module executing in the remote storage system receives the message identifying the modified file and copies a version of the file containing the modification from the virtual storage volume to a backup volume located in the remote storage system.

Abstract: Technologies are described herein for achieving data consistency during a failover from a primary node to a secondary node in a storage cluster with a shared RAID array in a degraded mode. When the primary storage node receives a write I/O operation, a volume module on the primary node reads the missing data strip data from the failed disk belonging to the stripe targeted by the write I/O operation. The primary storage node communicates the missing data strip to the secondary storage node, which writes the missing strip data to an outstanding strip log. Upon the failure of the primary node, the secondary storage node reads the missing data strip from the outstanding strip log and writes the missing data strip to the shared RAID array, thus restoring data consistency to the stripe of the RAID array containing the missing data strip.

Abstract: Technologies are described herein for achieving data consistency during a failover from a primary node to a secondary node in a storage cluster with a shared RAID array in a degraded mode. When the primary storage node receives a write I/O operation, a volume module on the primary node reads the missing data strip data from the failed disk belonging to the stripe targeted by the write I.O operation. The primary storage node communicates the missing data strip to the secondary storage node, which writes the missing strip data to an outstanding strip log. Upon the failure of the primary node, the secondary storage node reads the missing data strip from the outstanding strip log and writes the missing data strip to the shared RAID array, thus restoring data consistency to the stripe of the RAID array containing the missing data strip.

Abstract: Technologies are described herein for providing file-level CDP of files stored on a remote storage system. A client module executing on a client computer monitors for modifications made at the client computer to files or folders stored on a virtual storage volume provided by the remote storage system. Upon detecting a modification of a monitored file, the client module sends a message to the remote storage system identifying the file. A server module executing in the remote storage system receives the message identifying the modified file and copies a version of the file containing the modification from the virtual storage volume to a backup volume located in the remote storage system.