Abstract: A new snapshot of a storage volume is created by suppressing write requests. Once pending write requests from the computing nodes are completed, storage nodes create a new snapshot for the storage volume by allocating a new segment to the new snapshot. Data is written in segments and Metadata is stored in the segments indicating LBAs of data stored therein and offsets within the segments at which data for LBAs are stored. For write requests, index entries are stored in an index buffer for a segment and written to the segment when the buffer is full. A redo entry is created in a redo buffer for multiple storage volumes and slices for each write request. Write requests are acknowledged when the redo buffer is written to redo segments on a storage device. On restart, index buffers are reconstructed from the redo segments if needed.

Abstract: A new snapshot of a storage volume is created by suppressing write requests. Once pending write requests from the computing nodes are completed, storage nodes create a new snapshot for the storage volume by allocating a new segment to the new snapshot. Subsequent write requests to the storage volume are then performed on the segments allocated to the new snapshot. A block map records segments where current data for an LBA of a slice of a storage volume is stored. Block maps may be written to a storage device in order to free memory. Block maps may be read back into memory when needed. Writing and reading of block maps may be performed upon fragments of block maps. On restarting of the storage node, block maps may be restored from block maps stored in the storage device.

Abstract: A system maintains a consistency database that maintains a status (current, down, stale) for copies of logical storage volumes stored on storage nodes. As failures are detected, the consistency database is updated. Copies are synchronized with one another using information in the consistency database. Write operations on a primary node for a slice of a logical storage node are assigned a virtual block address (VBA) that is mapped to a logical block address (LBA) within the slice. Consistency of the VBAs of the primary node and that of a secondary node is evaluated and used to detect currency. VBA holes are detected and corresponding write commands resent to maintain currency. Physical segments on the primary node are assigned virtual segment identifiers (VSID) that are maintained consistent with VSIDs on clone nodes so that they can be used for garbage collection and synchronization.

Abstract: One or more techniques and/or computing devices are provided for resynchronization. For example, a request may be received to create pseudo snapshots of a first consistency group, hosted by a first storage controller, and a second consistency group, hosted by a second storage controller, having a synchronous replication relationship with the first consistency group. Incoming client write requests are logged within an intercept tracking log at the first storage controller. After a first drain without hold of incoming write requests is performed, a first pseudo common snapshot of the second consistency group is created. After a second drain without hold of incoming write operations is performed, a second pseudo common snapshot of the first consistency group and the intercept tracking log is created. The pseudo snapshots and the intercept tracking log (e.g., indicating a delta between the pseudo snapshots) are used to resynchronize the first and second consistency groups.

Abstract: A new snapshot of a storage volume is created by instructing computing nodes to suppress write requests. Once pending write requests from the computing nodes are completed, storage nodes create a new snapshot for the storage volume by allocating a new segment to the new snapshot and finalizes and performs garbage collection with respect to segments allocated to the previous snapshot. The snapshots may be represented by a storage manager in a hierarchy. Deleted snapshots may be flagged as such in the hierarchy and deletion may be implemented only in memory on a storage node, which is then restored from the hierarchy in the event of a crash. A snapshot is removed from the hierarchy when all segments previously are freed by garbage collection. A hybrid storage node may perform both computing and storage services. Data may be written with tags indicating encoding protocols used to encode the data.

Abstract: A new snapshot of a storage volume is created by instructing computing nodes to suppress write requests. Once pending write requests from the computing nodes are completed, storage nodes create a new snapshot for the storage volume by allocating a new segment to the new snapshot and finalizes and performs garbage collection with respect to segments allocated to the previous snapshot. The snapshots may be represented by a storage manager in a hierarchy. Deleted snapshots may be flagged as such in the hierarchy and deletion may be implemented only in memory on a storage node, which is then restored from the hierarchy in the event of a crash. A hybrid storage node may perform both computing and storage services. An IO module determines whether IOPs reference a locally-mounted storage device or a remote storage device. The IO module issues a library call for local IOPs using a shared memory in kernel space.

Abstract: A new snapshot of a storage volume is created by instructing computing nodes to suppress write requests. Once pending write requests from the computing nodes are completed, storage nodes create a new snapshot for the storage volume by allocating a new segment to the new snapshot and finalizes and performs garbage collection with respect to segments allocated to the previous snapshot. The snapshots may be represented by a storage manager in a hierarchy. Deleted snapshots may be flagged as such in the hierarchy and deletion may be implemented only in memory on a storage node, which is then restored from the hierarchy in the event of a crash. A snapshot is removed from the hierarchy when all segments previously are freed by garbage collection. A hybrid storage node may perform both computing and storage services. Data may be written with tags indicating encoding protocols used to encode the data.

Abstract: A system maintains a consistency database that maintains a status (current, down, stale) for copies of logical storage volumes stored on storage nodes. As failures are detected, the consistency database is updated. Copies are synchronized with one another using information in the consistency database. Write operations on a primary node for a slice of a logical storage node are assigned a virtual block address (VBA) that is mapped to a logical block address (LBA) within the slice. Consistency of the VBAs of the primary node and that of a secondary node is evaluated and used to detect currency. VBA holes are detected and corresponding write commands resent to maintain currency. Physical segments on the primary node are assigned virtual segment identifiers (VSID) that are maintained consistent with VSIDs on clone nodes so that they can be used for garbage collection and synchronization.

Abstract: A new snapshot of a storage volume is created by instructing computing nodes to suppress write requests. Once pending write requests from the computing nodes are completed, storage nodes create a new snapshot for the storage volume by allocating a new segment to the new snapshot and finalizes and performs garbage collection with respect to segments allocated to the previous snapshot. The snapshots may be represented by a storage manager in a hierarchy. Deleted snapshots may be flagged as such in the hierarchy and deletion may be implemented only in memory on a storage node, which is then restored from the hierarchy in the event of a crash. A snapshot is removed from the hierarchy when all segments previously are freed by garbage collection. A hybrid storage node may perform both computing and storage services. Data may be written with tags indicating encoding protocols used to encode the data.

Abstract: A new snapshot of a storage volume is created by instructing computing nodes to suppress write requests. Once pending write requests from the computing nodes are completed, storage nodes create a new snapshot for the storage volume by allocating a new segment to the new snapshot and finalizes and performs garbage collection with respect to segments allocated to the previous snapshot. The snapshots may be represented by a storage manager in a hierarchy. Deleted snapshots may be flagged as such in the hierarchy and deletion may be implemented only in memory on a storage node, which is then restored from the hierarchy in the event of a crash. A snapshot is removed from the hierarchy when all segments previously are freed by garbage collection. A hybrid storage node may perform both computing and storage services. Data may be written with tags indicating encoding protocols used to encode the data.

Abstract: A system maintains a consistency database that maintains a status (current, down, stale) for copies of logical storage volumes stored on storage nodes. As failures are detected, the consistency database is updated. Copies are synchronized with one another using information in the consistency database. Write operations on a primary node for a slice of a logical storage node are assigned a virtual block address (VBA) that is mapped to a logical block address (LBA) within the slice. Consistency of the VBAs of the primary node and that of a secondary node is evaluated and used to detect currency. VBA holes are detected and corresponding write commands resent to maintain currency. Physical segments on the primary node are assigned virtual segment identifiers (VSID) that are maintained consistent with VSIDs on clone nodes so that they can be used for garbage collection and synchronization.

Abstract: A system maintains a consistency database that maintains a status (current, down, stale) for copies of logical storage volumes stored on storage nodes. As failures are detected, the consistency database is updated. Copies are synchronized with one another using information in the consistency database. Write operations on a primary node for a slice of a logical storage node are assigned a virtual block address (VBA) that is mapped to a logical block address (LBA) within the slice. Consistency of the VBAs of the primary node and that of a secondary node is evaluated and used to detect currency. VBA holes are detected and corresponding write commands resent to maintain currency. Physical segments on the primary node are assigned virtual segment identifiers (VSID) that are maintained consistent with VSIDs on clone nodes so that they can be used for garbage collection and synchronization.

Abstract: One or more techniques and/or computing devices are provided for resynchronization. For example, a request may be received to create pseudo snapshots of a first consistency group, hosted by a first storage controller, and a second consistency group, hosted by a second storage controller, having a synchronous replication relationship with the first consistency group. Incoming client write requests are logged within an intercept tracking log at the first storage controller. After a first drain without hold of incoming write requests is performed, a first pseudo common snapshot of the second consistency group is created. After a second drain without hold of incoming write operations is performed, a second pseudo common snapshot of the first consistency group and the intercept tracking log is created. The pseudo snapshots and the intercept tracking log (e.g., indicating a delta between the pseudo snapshots) are used to resynchronize the first and second consistency groups.

Abstract: One or more techniques and/or computing devices are provided for resynchronization. For example, a request may be received to create pseudo snapshots of a first consistency group, hosted by a first storage controller, and a second consistency group, hosted by a second storage controller, having a synchronous replication relationship with the first consistency group. Incoming client write requests are logged within an intercept tracking log at the first storage controller. After a first drain without hold of incoming write requests is performed, a first pseudo common snapshot of the second consistency group is created. After a second drain without hold of incoming write operations is performed, a second pseudo common snapshot of the first consistency group and the intercept tracking log is created. The pseudo snapshots and the intercept tracking log (e.g., indicating a delta between the pseudo snapshots) are used to resynchronize the first and second consistency groups.

Abstract: One or more techniques and/or computing devices are provided for resynchronization. For example, a request may be received to create pseudo snapshots of a first consistency group, hosted by a first storage controller, and a second consistency group, hosted by a second storage controller, having a synchronous replication relationship with the first consistency group. Incoming client write requests are logged within an intercept tracking log at the first storage controller. After a first drain without hold of incoming write requests is performed, a first pseudo common snapshot of the second consistency group is created. After a second drain without hold of incoming write operations is performed, a second pseudo common snapshot of the first consistency group and the intercept tracking log is created. The pseudo snapshots and the intercept tracking log (e.g., indicating a delta between the pseudo snapshots) are used to resynchronize the first and second consistency groups.