# Disaster Recovery In the event of unrecoverable JetStream message persistence on one (or more) server nodes, there are two recovery scenarios: * Automatic recovery from intact quorum nodes * Manual recovery from existing stream snapshots (backups) {% hint style="danger" %} For R1 streams, data is persisted on one server node only. If that server node is unrecoverable then recovery from backup is the sole option. {% endhint %} ## Automatic Recovery NATS will create replacement stream replicas automatically under the following conditions: * Impacted stream is of replica configuration R3 (or greater) * Remaining intact nodes (stream replicas) meet minimum RAFT quorum: floor(R/2) + 1 * Available node(s) in the stream's cluster for new replica(s) * Impacted node(s) removed from the stream's domain RAFT Meta group (e.g. `nats server cluster peer-remove`) ## Manual Recovery Snapshots (also known as backups) can pro-actively be made of any stream regardless of replication configuration. The backup includes (by default): * Stream configuration and state * Stream durable consumer configuration and state * All message payload data including metadata like timestamps and headers ### Backup The `nats stream backup` CLI command is used to create snapshots of a stream and its durable consumers. {% hint style="info" %} As an account owner, if you wish to make a backup of ALL streams in your account, you may use `nats account backup` instead. {% endhint %} {% hint style="warning" %} Memory storage streams do not support snapshots. Only file-based storage streams can be backed up. {% endhint %} ```shell nats stream backup ORDERS '/data/js-backup/backup1' ``` Output ``` Starting backup of Stream "ORDERS" with 13 data blocks 2.4 MiB/s [====================================================================] 100% Received 13 MiB bytes of compressed data in 3368 chunks for stream "ORDERS" in 1.223428188s, 813 MiB uncompressed ``` During a backup operation, the stream is placed in a status where it's configuration cannot change and no data will be evicted based on stream retention policies. {% hint style="info" %} Progress using the terminal bar can be disabled using `--no-progress`, it will then issue log lines instead. {% endhint %} ### Restore An existing backup (as above) can be restored to the same or a new NATS server (or cluster) using the `nats stream restore` command. {% hint style="info" %} `nats stream restore` restores a single stream from one backup directory. To restore all streams at once, use `nats account restore` as described below. {% endhint %} ```shell nats stream restore '/data/js-backup/backup1' ``` Output ``` Starting restore of Stream "ORDERS" from file "/data/js-backup/backup1" 13 MiB/s [====================================================================] 100% Restored stream "ORDERS" in 937.071149ms Information for Stream ORDERS Configuration: Subjects: ORDERS.> ... ``` Progress using the terminal bar can be disabled using `--no-progress`, it will then issue log lines instead. ## Account-Level Backup and Restore In environments where the `nats` CLI is used interactively to configure the server you do not have a desired state to recreate the server from. This is not the ideal way to administer the server, we recommend Configuration Management, but many will use this approach. The `nats account backup` and `nats account restore` commands allow you to back up and restore all streams in an account at once, including their configuration, consumer state, and all message data. ### Account Backup ```shell nats account backup /data/js-backup ``` Output ``` Performing backup of all streams to /data/js-backup Streams: 3 Size: 14 KiB Consumers: 2 Starting backup of Stream "EVENTS" with 0 B Received 1.5 KiB compressed data in 2 chunks for stream "EVENTS" in 0s, 16 KiB uncompressed Starting backup of Stream "ORDERS" with 55 B Received 976 B compressed data in 2 chunks for stream "ORDERS" in 1ms, 9.5 KiB uncompressed Starting backup of Stream "WORK" with 7.3 KiB Received 7.3 KiB compressed data in 2 chunks for stream "WORK" in 0s, 30 KiB uncompressed ``` This creates a subdirectory per stream inside `/data/js-backup`, each containing the full stream snapshot (configuration, consumer state, and message data) in the same format as `nats stream backup`. Available flags for `nats account backup`: | Flag | Description | | --------------------- | -------------------------------------------- | | `--consumers` | Include consumer configuration and state | | `--check` | Check backup integrity | | `--force` | Force overwrite of existing backup directory | | `--critical-warnings` | Treat warnings as critical errors | ### Account Restore ```shell nats account restore /data/js-backup ``` Output ``` Restoring backup of all 3 streams in directory "/data/js-backup" Starting restore of Stream "EVENTS" from file "/data/js-backup/EVENTS" Restored stream "EVENTS" in 0s ... Starting restore of Stream "ORDERS" from file "/data/js-backup/ORDERS" Restored stream "ORDERS" in 1ms ... Starting restore of Stream "WORK" from file "/data/js-backup/WORK" Restored stream "WORK" in 0s ... ``` This restores all stream subdirectories found in `/data/js-backup`, including their full message data and consumer state. Available flags for `nats account restore`: | Flag | Description | | ----------- | ----------------------------------- | | `--cluster` | Target cluster for restored streams | | `--tag` | Placement tag for restored streams | {% hint style="warning" %} `nats account restore` will fail if a stream with the same name already exists. You must remove the existing stream before restoring from backup. {% endhint %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.nats.io/running-a-nats-service/nats_admin/jetstream_admin/disaster_recovery.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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