> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt # Glossary of Ops Manager Terms and Concepts agent A lightweight program that provides an interface between your MongoDB processes and Ops Manager. agent API key A unique identifier that authenticates a project's [MongoDB Agents](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) to Ops Manager. A project can have multiple agent API (Application Programming Interface) keys. **See also:** [Manage Agent API Keys](https://www.mongodb.com/docs/ops-manager/current/tutorial/manage-agent-api-key.md#std-label-om-manage-agent-api-key) application database The dedicated set of MongoDB databases that store metadata for the Ops Manager installation and the managed MongoDB deployments. **See also:** [Ops Manager Application Database](https://www.mongodb.com/docs/ops-manager/current/core/system-overview.md#std-label-mms-application-database) authentication mechanism A method to enable access to a MongoDB database. This is separate from authorization, which grants you permission to use certain actions on a MongoDB database. **See also:** [Configure MongoDB Authentication and Authorization](https://www.mongodb.com/docs/ops-manager/current/tutorial/edit-host-authentication-credentials.md#std-label-om-edit-host-authentication-credentials) automation The assisted management of MongoDB processes through the Ops Manager interface. The [MongoDB Agents](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) installed on your MongoDB hosts allow you to deploy, configure, and update MongoDB processes directly from Ops Manager. **See also:** [Automation](https://www.mongodb.com/docs/ops-manager/current/application.md#std-label-automation) Automation Agent The lightweight component that had automated common management tasks. The Automation Agent runs on every server that ran a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) or [`mongos`.](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) **Note:** This has been replaced with the [MongoDB Agent.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) backing databases The collective term for the sets of MongoDB databases that support an Ops Manager deployment: the [application database](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-application-database) and the [backup database(s).](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-Backup-Database) **See also:** [Install the Ops Manager Application Database and Backup Database](https://www.mongodb.com/docs/ops-manager/current/tutorial/prepare-backing-mongodb-instances.md#std-label-om-install-backing-dbs) Backup Agent The lightweight component that had run within your data center and backed up MongoDB processes via the MongoDB wire protocol. No direct file system access was needed. **Note:** This has been replaced with the [MongoDB Agent.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) backup blockstore database The database that stores your [snapshots](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-snapshot). The database is also referred to simply as the *blockstore.* The blockstore uses a storage format that parses a snapshot into [smaller chunks](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-block) that allow Ops Manager to manage snapshot changes. You can administer blockstores from the [Snapshot Storage](https://www.mongodb.com/docs/ops-manager/current/admin/backup/snapshot-storage-page.md#std-label-blockstores-page). The blockstore is one type of [Backup Database.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-Backup-Database) backup cursor A [tailable cursor](https://www.mongodb.com/docs/manual/core/tailable-cursors.md#std-label-tailable-cursors-landing-page) pointing to a list of backup files. Starting with FCV 4.2, Ops Manager uses [backup cursors](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-backup-cursor) instead of [head databases.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-head-database) Backup Daemon A required headless service to the Ops Manager Application that is responsible for backup [snapshot](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-snapshot) maintenance work, such as a [groom](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-groom) and managing file system snapshot files on the [file system store](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-File-System-Store) While we no longer use a [head database](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-head-database) for backup snapshots, Backup Daemons are still a required component for Ops Manager backups and [queryable backup](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-queryable-backup) to function. **See also:** [Backup Daemon Service](https://www.mongodb.com/docs/ops-manager/current/core/system-overview.md#std-label-backup-daemon) Backup Database The set of databases where onprem stores backup data. This includes the [Oplog Store Database](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-Oplog-Store-Database) and any [backup blockstore database](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-backup-blockstore-database) or [S3 Snapshot Store](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-S3-Snapshot-Store) metadata database deployed. **See also:** - [Snapshot Storage](https://www.mongodb.com/docs/ops-manager/current/core/system-overview.md#std-label-backup-database) - [Backup Process](https://www.mongodb.com/docs/ops-manager/current/core/backup-overview.md#std-label-backup-overview) backup job The Ops Manager process that backs up MongoDB deployments. The WiredTiger storage engine takes snapshots of your deployment using [backup cursors](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-backup-cursor) to allow point-in-time copying of the WiredTiger files. Applications can continue read and write operations on the database while WiredTiger takes the snapshot. You can re-assign backup jobs among Backup Daemons. **See also:** [Jobs](https://www.mongodb.com/docs/ops-manager/current/admin/backup/jobs-page.md#std-label-jobs-page) batch The collection of jobs needed to restore a [sharded cluster](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-sharded-cluster): one job for each shard and one job for the [config server.](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-config-server) Replica set restore jobs do not use batches. block A MongoDB document that stores the compressed contents of a 64 KB to 16 MB slice of the data and metadata of a file included in a snapshot. In dividing the snapshot, Ops Manager can back up data block by block instead of writing whole new copies of a snapshot. blockstore See [backup blockstore database.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-backup-blockstore-database) cluster In Ops Manager, *cluster* can refer to either a [replica set](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-replica-set) or [sharded cluster.](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-sharded-cluster) conf call A request from a [MongoDB Agent](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) to Ops Manager to get the latest configuration for that Agent's project including the nodes to which the Agent connects and what data to back up. custom snapshot A backup of the state of your MongoDB deployment at a point in time between [stored snapshots](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-snapshot). Ops Manager builds a custom snapshot by applying oplog data to a stored snapshot. **See also:** [Restore Overview](https://www.mongodb.com/docs/ops-manager/current/tutorial/nav/restore-overview.md#std-label-restore-overview) deduplication A process that eliminates redundant data. This data can be additional copies of database or file system documents or redundant data within those documents at the block level when written to a storage medium like spinning or solid state disks. Only unique documents or blocks are written to a storage medium. This process usually applies to backups or data archiving. For example, each recipient in an email system may have their own copy of an email sent to the whole company. With deduplication, all copies of this except one are replaced with pointers to a single stored copy before backing up the email system. This reduces the amount of storage capacity needed to back up this one email by 99 percent. deployment Usually refers to all the MongoDB processes that run within an Ops Manager [project](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-project). *Deployment* can also refer to a specific set of MongoDB processes, such as a specific [sharded cluster](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-sharded-cluster) or [replica set.](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-replica-set) dirty bytes Data that has been updated in the WiredTiger cache but not flushed to disk. excluded namespace A database or collection that Ops Manager will not back up, as designated by its [namespace.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-namespace) **See also:** [Namespaces Filter](https://www.mongodb.com/docs/ops-manager/current/core/backup-preparations.md#std-label-namespaces-filter) File System Store A directory on a server that stores your database backup [snapshots](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-snapshot) as files. You can administer file system storage from the [Snapshot Storage.](https://www.mongodb.com/docs/ops-manager/current/admin/backup/snapshot-storage-page.md#std-label-blockstores-page) groom A job that removes unused blocks on a [blockstore](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-backup-blockstore-database) and that can move blocks from one blockstore to another. You can view and manage grooms from [Grooms](https://www.mongodb.com/docs/ops-manager/current/admin/backup/grooms-page.md#std-label-grooms-page) and [Groom Priority.](https://www.mongodb.com/docs/ops-manager/current/admin/backup/groom-priority-page.md#std-label-groom-priority-page) group A distinct set of MongoDB processes and Ops Manager users. Synonymous with [project.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-project) **See also:** [Manage Projects](https://www.mongodb.com/docs/ops-manager/current/tutorial/manage-projects.md#std-label-om-manage-projects) head See [head database.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-head-database) head database The copy of a backed-up deployment stored on the [Backup Daemon's](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-Backup-Daemon) server. The daemon maintains a head database for each [shard](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-shard) or [replica set](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-replica-set) it backs up and creates periodic [snapshots](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-snapshot). The Daemon stores the head databases in the [head directory.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-head-directory) Starting with FCV 4.2, onprem uses [backup cursors](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-backup-cursor) instead of head databases. head directory The dedicated disk partition on the [Backup Daemon's](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-Backup-Daemon) host where the Backup Daemon stores the [head databases](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-head-database). The daemon writes to this directory as the `mongodb-mms` user. host A physical machine, virtual machine, or container that serves one or more MongoDB processes. initial sync The MongoDB operation that replicates data from an existing [replica set](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-replica-set) member to a new member. Ops Manager uses initial sync when creating a new [head database.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-head-database) **See also:** - [Backup Process Flows](https://www.mongodb.com/docs/ops-manager/current/core/backup-overview.md#std-label-backup-initial-sync) - [Replica Set Data Synchronization](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-sync) in the MongoDB manual job See [backup job.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-backup-job) link-token A string that contains the information necessary to connect from Ops Manager to Atlas during a Live Migration from an Ops Manager deployment to a deployment in Atlas. migration host A dedicated server with its own specially-configured MongoDB Agent configured for live migration. You run the Live Migration (push) process on the migration host to migrate your MongoDB deployment to Atlas. **See also:** - [Provision a Migration Host for MongoDB Agent](https://www.mongodb.com/docs/ops-manager/current/tutorial/provision-migration-host.md#std-label-provision-migration-host) - [Migrate from Ops Manager to Atlas](https://www.mongodb.com/docs/ops-manager/current/tutorial/migrate-to-atlas.md#std-label-migrate-to-atlas) MongoDB Agent A lightweight [agent](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-agent) that can monitor, manage, and back up your MongoDB databases. **See also:** [MongoDB Agent](https://www.mongodb.com/docs/ops-manager/current/tutorial/nav/mongodb-agent.md#std-label-mongodb-agent) monitoring The real-time reporting, visualization, and alerting of the state of your MongoDB processes. **See also:** [Monitoring](https://www.mongodb.com/docs/ops-manager/current/application.md#std-label-monitoring-functional-overview) Monitoring Agent The lightweight component that had run within your data center and monitored your MongoDB processes via the MongoDB wire protocol. No direct file system access was needed. **Note:** This has been replaced with the [MongoDB Agent.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) namespace The combination of the database name and collection name: ```javascript "database-name.collection-name" ``` oplog slice A compressed batch of entries for the tailed [oplog](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-oplog) of a backed-up shard or replica set. The [MongoDB Agent](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) creates an oplog slice and sends it to Ops Manager, which stores it in the [Oplog Store Database.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-Oplog-Store-Database) Ops Manager retrieves the slice and stores it in the [Oplog Store Database.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-Oplog-Store-Database) **See also:** [Oplog Stores](https://www.mongodb.com/docs/ops-manager/current/admin/backup/oplog-stores-page.md#std-label-oplog-stores-page) Oplog Store Database The database where Ops Manager stores [oplog slices](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-oplog-slice) before applying them to a deployment's backup. **See also:** [Oplog Stores](https://www.mongodb.com/docs/ops-manager/current/admin/backup/oplog-stores-page.md#std-label-oplog-stores-page) Ops Manager Application The main Ops Manager component. The application provides the user interface for managing MongoDB deployments and provides endpoints for [MongoDB Agents](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) to transmit data. **See also:** [Ops Manager Application](https://www.mongodb.com/docs/ops-manager/current/core/system-overview.md#std-label-mms-application-package) Ops Manager HTTP Service The interface through which the [MongoDB Agent](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) communicates with Ops Manager. **See also:** [Ops Manager Application](https://www.mongodb.com/docs/ops-manager/current/core/system-overview.md#std-label-mms-http-service) ping A data transmission that the [MongoDB Agent](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-MongoDB-Agent) sends to Ops Manager to confirm that the Agent and its MongoDB processes are running and reachable. point-in-time restore A database restoration that captures the state of your data at a moment in-between [snapshots](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-snapshot). Point-in-time restores take longer to perform than snapshot restores. **See also:** [Restore Overview](https://www.mongodb.com/docs/ops-manager/current/tutorial/nav/restore-overview.md#std-label-restore-overview) process An instance of MongoDB running on a given host and port. The MongoDB database process is [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod). MongoDB also uses the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) process to route operations in the [sharded clusters.](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-sharded-cluster) **See also:** [MongoDB Package Components](https://www.mongodb.com/docs/manual/reference/program.md#std-label-mongodb-package-components) project A distinct set of MongoDB processes and Ops Manager users. Synonymous with [group.](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-group) **See also:** [Manage Projects](https://www.mongodb.com/docs/ops-manager/current/tutorial/manage-projects.md#std-label-om-manage-projects) Public API key A unique identifier that authenticates an Ops Manager user through the [Ops Manager Administration API](https://www.mongodb.com/docs/ops-manager/current/core/api.md#std-label-public-api-principles). The key belongs to the user, as opposed to the [agent API key](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-agent-API-key), which belongs to the project. queryable backup A feature provided by Ops Manager in which Ops Manager quickly and securely makes a given snapshot accessible over a MongoDB connection string. You can use the connection string with standard MongoDB tools such as [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) or mongodump to access the snapshot for read-only operations. Queryable backups start up quickly regardless of the snapshot's total data size. They are uniquely useful for restoring a small subset of data, such as a document that was accidentally deleted, or reading out a single collection with mongodump. **See also:** [Query a Backup Snapshot](https://www.mongodb.com/docs/ops-manager/current/tutorial/query-backup.md#std-label-om-query-backup) Recovery Point Objective The maximum tolerable age of backup files that must be recovered from storage for normal operations to resume after a failure or disaster occurs. Recovery Time Objective The maximum tolerable length of time that a system can be offline after a failure or disaster occurs. role The permissions granted to an Ops Manager or MongoDB user. **See also:** - [Ops Manager Roles](https://www.mongodb.com/docs/ops-manager/current/reference/user-roles.md#std-label-user-roles) for Ops Manager user roles - [Built-in Roles](https://www.mongodb.com/docs/manual/reference/built-in-roles.md#std-label-built-in-roles) in the MongoDB manual for MongoDB user roles rolling restart A technique used to maintain cluster availability during maintenance periods by updating nodes in a replica set one-by-one, always maintaining a primary node, until all nodes are updated. **See also:** [How does Ops Manager perform maintenance on cluster nodes?](https://www.mongodb.com/docs/ops-manager/current/reference/faq/faq-automation.md#std-label-rolling-restart-faq) S3 Snapshot Store An s3 bucket in aws that stores your database backup [snapshots](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-snapshot) as blocks. You can administer s3 blockstore storage from the [Snapshot Storage.](https://www.mongodb.com/docs/ops-manager/current/admin/backup/snapshot-storage-page.md#std-label-blockstores-page) **See also:** [Manage S3-Compatible Snapshot Storage](https://www.mongodb.com/docs/ops-manager/current/tutorial/manage-s3-blockstore-storage.md#std-label-manage-s3-snapshot-store) server A physical or virtual machine that serves one or more MongoDB processes. snapshot Single backup of your data that Ops Manager captures at a specific interval and stores as a snapshot in one of the following locations: - [blockstore](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-backup-blockstore-database) - [file system stores](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-File-System-Store) - [S3 snapshot stores](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-S3-Snapshot-Store) Ops Manager creates snapshots from [secondaries.](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-secondary) The [Snapshot Frequency and Retention Policy](https://www.mongodb.com/docs/ops-manager/current/core/backup-preparations.md#std-label-snapshot-frequency-and-retention) determines the interval for taking snapshots and how long to store them. **See also:** - [Backup Process](https://www.mongodb.com/docs/ops-manager/current/core/backup-overview.md#std-label-backup-overview) - [custom snapshot](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-custom-snapshot) snapshot frequency and retention policy The schedule for how often to take [snapshots](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-snapshot) and how long to store them. **See also:** [Snapshot Frequency and Retention Policy](https://www.mongodb.com/docs/ops-manager/current/core/backup-preparations.md#std-label-snapshot-frequency-and-retention) snapshot store The location where your [snapshots](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-snapshot) are stored. There are multiple types of snapshot stores, including: - [file system stores](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-File-System-Store) - [Blockstores](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-backup-blockstore-database) - [S3 snapshot stores](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-S3-Snapshot-Store) storage engine The database storage engine manages how data is stored on disk. MongoDB versions 3.0 and later offer multiple storage engines. **See also:** - [Storage Engines](https://www.mongodb.com/docs/manual/core/storage-engines.md#std-label-storage-engines) - [MongoDB Storage FAQ](https://www.mongodb.com/docs/manual/faq/storage.md#std-label-faq-storage) in the MongoDB manual sync store During [initial sync](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-initial-sync) of a backed-up deployment, Ops Manager briefly stores slices of the backed-up deployment in a temporary sync store on the [Oplog Store Database](https://www.mongodb.com/docs/ops-manager/current/reference/glossary.md#std-term-Oplog-Store-Database). Ops Manager uses the storage while streaming slices to the Backup Daemon. version manifest List of all released MongoDB versions that a particular version of Ops Manager supports. Ops Manager uses this list if running in [local mode.](https://www.mongodb.com/docs/ops-manager/current/tutorial/configure-local-mode.md#std-label-om-modes)