---
layout: docs
page_title: Raft - Storage Backends - Configuration
sidebar_title: Raft
description: |-

  The Raft storage backend is used to persist Vault's data. Unlike all the other
  storage backends, this backend does not operate from a single source for the
  data. Instead all the nodes in a Vault cluster will have a replicated copy of
  the entire data. The data is replicated across the nodes using the Raft
  Consensus Algorithm.
---

# Raft Storage Backend

The Raft storage backend is used to persist Vault's data. Unlike other storage
backends, Raft storage does not operate from a single source of data. Instead
all the nodes in a Vault cluster will have a replicated copy of Vault's data.
Data gets replicated across the all the nodes via the [Raft Consensus
Algorithm][raft].

- **High Availability** – the Raft storage backend supports high availability.

- **HashiCorp Supported** – the Raft storage backend is officially supported
  by HashiCorp.

```hcl
storage "raft" {
  path = "/path/to/raft/data"
  node_id = "raft_node_1"
}
cluster_addr = "http://127.0.0.1:8201"
```

~> **Note:** When using the Raft storage backend, it is required to provide
`cluster_addr` to indicate the address and port to be used for communication
between the nodes in the Raft cluster.

~> **Note:** When using the Raft storage backend, a separate `ha_storage`
backend cannot be declared.

~> **Note:** When using the Raft storage backend, it is strongly recommended to
set `disable_mlock` to `true`, and to disable memory swapping on the system.

## `raft` Parameters

- `path` `(string: "")` – The file system path where all the Vault data gets
  stored.
  This value can be overridden by setting the `VAULT_RAFT_PATH` environment variable.

- `node_id` `(string: "")` - The identifier for the node in the Raft cluster.
  This value can be overridden by setting the `VAULT_RAFT_NODE_ID` environment variable.

- `performance_multiplier` `(integer: 0)` - An integer multiplier used by
  servers to scale key Raft timing parameters. Tuning this affects the time it
  takes Vault to detect leader failures and to perform leader elections, at the
  expense of requiring more network and CPU resources for better performance.
  Omitting this value or setting it to 0 uses default timing described below.
  Lower values are used to tighten timing and increase sensitivity while higher
  values relax timings and reduce sensitivity.

  By default, Vault will use a lower-performance timing that's suitable for
  minimal Vault servers, currently equivalent to setting this to a value of 5
  (this default may be changed in future versions of Vault, depending if the
  target minimum server profile changes). Setting this to a value of 1 will
  configure Raft to its highest-performance mode and is recommended for
  production Vault servers. The maximum allowed value is 10.

- `trailing_logs` `(integer: 10000)` - This controls how many log entries are
  left in the log store on disk after a snapshot is made. This should only be
  adjusted when followers cannot catch up to the leader due to a very large
  snapshot size and high write throughput causing log truncation before a
  snapshot can be fully installed. If you need to use this to recover a cluster,
  consider reducing write throughput or the amount of data stored on Vault. The
  default value is 10000 which is suitable for all normal workloads.

- `snapshot_threshold` `(integer: 8192)` - This controls the minimum number of raft
  commit entries between snapshots that are saved to disk. This is a low-level
  parameter that should rarely need to be changed. Very busy clusters
  experiencing excessive disk IO may increase this value to reduce disk IO and
  minimize the chances of all servers taking snapshots at the same time.
  Increasing this trades off disk IO for disk space since the log will grow much
  larger and the space in the raft.db file can't be reclaimed till the next
  snapshot. Servers may take longer to recover from crashes or failover if this
  is increased significantly as more logs will need to be replayed.

- `retry_join` `(list: [])` - There can be one or more `retry_join` stanzas.
  When the raft cluster is getting bootstrapped, if the connection details of all
  the nodes are known beforehand, then specifying this config stanzas enables the
  nodes to automatically join a raft cluster. All the nodes would mention all
  other nodes that they could join using this config. When one of the nodes is
  initialized, it becomes the leader and all the other nodes will join the
  leader node to form the cluster. When using Shamir seal, the joined nodes will
  still need to be unsealed manually. See the section below that describes the
  parameters accepted by the `retry_join` stanza.

- `max_entry_size` `(integer: 1048576)` - This configures the maximum number of
  bytes for a raft entry. It applies to both Put operations and transactions.
  Any put or transaction operation exceeding this configuration value will cause
  the respective operation to fail. Raft has a suggested max size of data in a
  raft log entry. This is based on current architecture, default timing, etc.
  Integrated storage also uses a chunk size that is the threshold used for
  breaking a large value into chunks. By default, the chunk size is the same as
  raft's max size log entry. The default value for this configuration is 1048576
  -- two times the chunking size.

### `retry_join` stanza

- `leader_api_addr` `(string: "")` - Address of a possible leader node.

- `leader_ca_cert_file` `(string: "")` - File path to the CA cert of the
  possible leader node.

- `leader_client_cert_file` `(string: "")` - File path to the client certificate
for the follower node to establish client authentication with the possible
leader node.

- `leader_client_key_file` `(string: "")` - File path to the client key for the
follower node to establish client authentication with the possible leader node.

- `leader_ca_cert` `(string: "")` - CA cert of the possible leader node.

- `leader_client_cert` `(string: "")` - Client certificate for the follower node
to establish client authentication with the possible leader node.

- `leader_client_key` `(string: "")` - Client key for the follower node to
establish client authentication with the possible leader node.

Each `retry_join` block may provide TLS certificates via file paths or as a
single-line certificate string value with newlines delimited by `\n`, but not a
combination of both.

Example Configuration:
```
storage "raft" {
  path    = "/Users/foo/raft/"
  node_id = "node1"
  retry_join {
    leader_api_addr = "http://127.0.0.2:8200"
    leader_ca_cert_file = "/path/to/ca1"
    leader_client_cert_file = "/path/to/client/cert1"
    leader_client_key_file = "/path/to/client/key1"
  }
  retry_join {
    leader_api_addr = "http://127.0.0.3:8200"
    leader_ca_cert_file = "/path/to/ca2"
    leader_client_cert_file = "/path/to/client/cert2"
    leader_client_key_file = "/path/to/client/key2"
  }
  retry_join {
    leader_api_addr = "http://127.0.0.4:8200"
    leader_ca_cert_file = "/path/to/ca3"
    leader_client_cert_file = "/path/to/client/cert3"
    leader_client_key_file = "/path/to/client/key3"
  }
}
```

[raft]: https://raft.github.io/ 'The Raft Consensus Algorithm'