Abstract: In some examples, a duster comprises peer nodes and a distributed data store implemented across the peer nodes, a method of remote linking of data objects for data transfer between a first node cluster and a second node cluster among the peer nodes; the method comprising: creating a data object group including multiple remote data objects, wherein a plurality of remote data objects in the data object group represent a same first virtual machine and are registrable on at least the first and second node clusters of the peer DMS nodes; creating or identifying remote links to a plurality of the remote data objects in the data object group; designating a member of the data object group as an active member of the group; and assigning a task to the active member to be completed using remote links.

Abstract: A computing system may repair a database index for a database table by placing a first structural lock on the database table to prevent modifications to the structure of the table. The computing system may scan the database table to determine a plurality of database records. The system may probe the database index for the database records to identify records with missing entries in the index. Based on the probing, the system may place a first data lock on a record of the database table corresponding to a missing index entry to prevent modification of data in the record. In response to placing the first record lock, the system adds an index entry for the locked database record to the database index. During repair of the index, one or more processes may use the database index to locate one of the plurality of database records included in the database table.

Abstract: Techniques are disclosed relating to compressing database keys. A computer system may receive a request to write a database record to a storage medium. The database record may include a database key and a corresponding data value. The computer system may compress the database key by replacing a portion of the database key with particular data that identifies a location of a reference database key and an amount of similarity determined between the database key and the reference database key. The computer system may write the database record to the storage medium. The database record may include the compressed database key and the corresponding data value.

Abstract: Techniques are disclosed relating to building an in-memory multi-level data structure useable to determine presence or absence of key ranges in files consisting of database records. In various embodiments, a computer system operates a database, including maintaining a set of records having a set of corresponding keys that are accessible in key-sorted order and generates a multi-level data structure that facilitates key range lookups against the set of records. The generating may include accessing ones of the set of keys in key-sorted order and determining, for a particular accessed key that includes a set of characters, an intermediate level within the multi-level data structure and a subset of the characters of the particular accessed key for insertion. The computer system may insert, starting at the intermediate level, information that identifies the subset of characters, with the inserting being performed without traversing any levels before the intermediate level.

Abstract: Techniques are disclosed relating to merge operations for multi-level data structures, such as log-structured merge-trees (LSM trees). A computer system may store, in a database, a plurality of files as part of an LSM tree and a plurality of database key structures. A given one of the plurality of database key structures may indicate, for a corresponding one of the plurality of files, a set of key ranges derived from database records that are included in the corresponding file. The computer system may determine, using ones of the plurality of database key structures, a key range overlap that is indicative of an extent of overlap of key ranges from a set of the plurality of files with respect to a particular key range. Based on the determined key range overlap, the computer system may assign a priority level to a merge operation that involves the set of files.

Abstract: In some examples, a data management and storage (DMS) cluster comprises peer DMS nodes and a distributed data store implemented across the peer DMS nodes. The peer DMS nodes are configured to collectively implement operations in a method of remote linking of snappables for data transfer between a first node cluster and a second node cluster among the peer DMS nodes.

Abstract: Techniques are disclosed relating to compressing database keys. A computer system may receive a request to write a database record to a storage medium. The database record may include a database key and a corresponding data value. The computer system may compress the database key by replacing a portion of the database key with particular data that identifies a location of a reference database key and an amount of similarity determined between the database key and the reference database key. The computer system may write the database record to the storage medium. The database record may include the compressed database key and the corresponding data value.

Abstract: Techniques are disclosed relating to probabilistic data structures. A database node may maintaining a probabilistic data structure capable of encoding database keys. The probabilistic data structure may include a plurality of levels that are each capable of storing an indication of a transition between successive characters in a database key. The database node may insert a particular database key into the probabilistic data structure and the particular database key may comprise a series of characters. The inserting may include setting, for each transition between successive characters of the series of characters, an indication in a corresponding level of the plurality of levels that is indicative of that transition. The database node may further maintain lineage information specifying one or more lineages that correspond to the transition.

Abstract: Methods and systems for reducing the data recovery time when failing back to a primary system from a secondary data backup system using virtual machine conversions and incremental exportation for backed-up virtual machine snapshots are described. Upon detection that the primary system is available to receive replicated snapshots for a virtual machine, the secondary data backup system may identify a first virtual machine snapshot out of a chain of snapshots for the virtual machine (e.g., the earliest in time snapshot within the chain or a middle snapshot in the middle of the chain) and transfer a full image snapshot for the first virtual machine snapshot to the primary system. Thereafter, data changes between the next virtual machine snapshot to be transferred to the primary system and the most-recently hydrated virtual machine on the primary system may be identified and then transferred to the primary system.

Abstract: A computing system may repair a database index for a database table by placing a first structural lock on the database table to prevent modifications to the structure of the table. The computing system may scan the database table to determine a plurality of database records. The system may probe the database index for the database records to identify records with missing entries in the index. Based on the probing, the system may place a first data lock on a record of the database table corresponding to a missing index entry to prevent modification of data in the record. In response to placing the first record lock, the system adds an index entry for the locked database record to the database index. During repair of the index, one or more processes may use the database index to locate one of the plurality of database records included in the database table.

Abstract: Techniques are disclosed relating to compressing database keys. A computer system may receive a request to write a database record to a storage medium. The database record may include a database key and a corresponding data value. The computer system may compress the database key by replacing a portion of the database key with particular data that identifies a location of a reference database key and an amount of similarity determined between the database key and the reference database key. The computer system may write the database record to the storage medium. The database record may include the compressed database key and the corresponding data value.

Abstract: Methods and systems for reducing the data recovery time when failing back to a primary system from a secondary data backup system using virtual machine conversions and incremental exportation for backed-up virtual machine snapshots are described. Upon detection that the primary system is available to receive replicated snapshots for a virtual machine, the secondary data backup system may identify a first virtual machine snapshot out of a chain of snapshots for the virtual machine (e.g., the earliest in time snapshot within the chain or a middle snapshot in the middle of the chain) and transfer a full image snapshot for the first virtual machine snapshot to the primary system. Thereafter, data changes between the next virtual machine snapshot to be transferred to the primary system and the most-recently hydrated virtual machine on the primary system may be identified and then transferred to the primary system.