Command Line Arguments

The NATS Streaming Server accepts command line arguments to control its behavior. There is a set of parameters specific to the NATS Streaming Server and some to the embedded NATS Server.

Command line parameters override corresponding config options in a configuration file, which themselves override configuration defaults. Configuration defaults can be found on the Configuration File page.

Note about parameters types



For booleans, either simply specify the parameter with value to enable (e.g -SD), or specify =false to disable


You can specify as a number 1024 or as a size 1KB


Values must be expressed in the form _h_m_s, such as 1h or 20s or 1h30m, or 1.5h, etc...

Usage: nats-streaming-server [options]

Streaming Server Options:
    -cid, --cluster_id  <string>         Cluster ID (default: test-cluster)
    -st,  --store <string>               Store type: MEMORY|FILE|SQL (default: MEMORY)
          --dir <string>                 For FILE store type, this is the root directory
    -mc,  --max_channels <int>           Max number of channels (0 for unlimited)
    -msu, --max_subs <int>               Max number of subscriptions per channel (0 for unlimited)
    -mm,  --max_msgs <int>               Max number of messages per channel (0 for unlimited)
    -mb,  --max_bytes <size>             Max messages total size per channel (0 for unlimited)
    -ma,  --max_age <duration>           Max duration a message can be stored ("0s" for unlimited)
    -mi,  --max_inactivity <duration>    Max inactivity (no new message, no subscription) after which a channel can be garbage collected (0 for unlimited)
    -ns,  --nats_server <string>         Connect to this external NATS Server URL (embedded otherwise)
    -sc,  --stan_config <string>         Streaming server configuration file
    -hbi, --hb_interval <duration>       Interval at which server sends heartbeat to a client
    -hbt, --hb_timeout <duration>        How long server waits for a heartbeat response
    -hbf, --hb_fail_count <int>          Number of failed heartbeats before server closes the client connection
          --ft_group <string>            Name of the FT Group. A group can be 2 or more servers with a single active server and all sharing the same datastore
    -sl,  --signal <signal>[=<pid>]      Send signal to nats-streaming-server process (stop, quit, reopen)
          --encrypt <bool>               Specify if server should use encryption at rest
          --encryption_cipher <string>   Cipher to use for encryption. Currently support AES and CHAHA (ChaChaPoly). Defaults to AES
          --encryption_key <string>      Encryption Key. It is recommended to specify it through the NATS_STREAMING_ENCRYPTION_KEY environment variable instead

Streaming Server Clustering Options:
    --clustered <bool>                   Run the server in a clustered configuration (default: false)
    --cluster_node_id <string>           ID of the node within the cluster if there is no stored ID (default: random UUID)
    --cluster_bootstrap <bool>           Bootstrap the cluster if there is no existing state by electing self as leader (default: false)
    --cluster_peers <string, ...>        Comma separated list of cluster peer node IDs to bootstrap cluster state
    --cluster_log_path <string>          Directory to store log replication data
    --cluster_log_cache_size <int>       Number of log entries to cache in memory to reduce disk IO (default: 512)
    --cluster_log_snapshots <int>        Number of log snapshots to retain (default: 2)
    --cluster_trailing_logs <int>        Number of log entries to leave after a snapshot and compaction
    --cluster_sync <bool>                Do a file sync after every write to the replication log and message store
    --cluster_raft_logging <bool>        Enable logging from the Raft library (disabled by default)

Streaming Server File Store Options:
    --file_compact_enabled <bool>        Enable file compaction
    --file_compact_frag <int>            File fragmentation threshold for compaction
    --file_compact_interval <int>        Minimum interval (in seconds) between file compactions
    --file_compact_min_size <size>       Minimum file size for compaction
    --file_buffer_size <size>            File buffer size (in bytes)
    --file_crc <bool>                    Enable file CRC-32 checksum
    --file_crc_poly <int>                Polynomial used to make the table used for CRC-32 checksum
    --file_sync <bool>                   Enable File.Sync on Flush
    --file_slice_max_msgs <int>          Maximum number of messages per file slice (subject to channel limits)
    --file_slice_max_bytes <size>        Maximum file slice size - including index file (subject to channel limits)
    --file_slice_max_age <duration>      Maximum file slice duration starting when the first message is stored (subject to channel limits)
    --file_slice_archive_script <string> Path to script to use if you want to archive a file slice being removed
    --file_fds_limit <int>               Store will try to use no more file descriptors than this given limit
    --file_parallel_recovery <int>       On startup, number of channels that can be recovered in parallel
    --file_truncate_bad_eof <bool>       Truncate files for which there is an unexpected EOF on recovery, dataloss may occur
    --file_read_buffer_size <size>       Size of messages read ahead buffer (0 to disable)
    --file_auto_sync <duration>          Interval at which the store should be automatically flushed and sync'ed on disk (<= 0 to disable)

Streaming Server SQL Store Options:
    --sql_driver <string>            Name of the SQL Driver ("mysql" or "postgres")
    --sql_source <string>            Datasource used when opening an SQL connection to the database
    --sql_no_caching <bool>          Enable/Disable caching for improved performance
    --sql_max_open_conns <int>       Maximum number of opened connections to the database

Streaming Server TLS Options:
    -secure <bool>                   Use a TLS connection to the NATS server without
                                     verification; weaker than specifying certificates.
    -tls_client_key <string>         Client key for the streaming server
    -tls_client_cert <string>        Client certificate for the streaming server
    -tls_client_cacert <string>      Client certificate CA for the streaming server

Streaming Server Logging Options:
    -SD, --stan_debug=<bool>         Enable STAN debugging output
    -SV, --stan_trace=<bool>         Trace the raw STAN protocol
    -SDV                             Debug and trace STAN
         --syslog_name               On Windows, when running several servers as a service, use this name for the event source
    (See additional NATS logging options below)

Embedded NATS Server Options:
    -a, --addr <string>              Bind to host address (default:
    -p, --port <int>                 Use port for clients (default: 4222)
    -P, --pid <string>               File to store PID
    -m, --http_port <int>            Use port for http monitoring
    -ms,--https_port <int>           Use port for https monitoring
    -c, --config <string>            Configuration file

Logging Options:
    -l, --log <string>               File to redirect log output
    -T, --logtime=<bool>             Timestamp log entries (default: true)
    -s, --syslog <string>            Enable syslog as log method
    -r, --remote_syslog <string>     Syslog server addr (udp://localhost:514)
    -D, --debug=<bool>               Enable debugging output
    -V, --trace=<bool>               Trace the raw protocol
    -DV                              Debug and trace

Authorization Options:
        --user <string>              User required for connections
        --pass <string>              Password required for connections
        --auth <string>              Authorization token required for connections

TLS Options:
        --tls=<bool>                 Enable TLS, do not verify clients (default: false)
        --tlscert <string>           Server certificate file
        --tlskey <string>            Private key for server certificate
        --tlsverify=<bool>           Enable TLS, verify client certificates
        --tlscacert <string>         Client certificate CA for verification

NATS Clustering Options:
        --routes <string, ...>       Routes to solicit and connect
        --cluster <string>           Cluster URL for solicited routes

Common Options:
    -h, --help                       Show this message
    -v, --version                    Show version
        --help_tls                   TLS help.