Configuration options

EventStoreDB has a number of configuration options that can be changed. You can find all the options described in details in this section.

When you don't change the configuration, EventStoreDB will use sensible defaults, but they might not suit your needs. You can always instruct EventStoreDB to use a different set of options. There are multiple ways to configure EventStoreDB server, described below.

Version and help

You can check what version of EventStoreDB you have installed by using the --version parameter in the command line. For example:

The full list of available options is available from the currently installed server by using the --help option in the command line.

Configuration file

You would use the configuration file when you want the server to run with the same set of options every time. YAML files are better for large installations as you can centrally distribute and manage them, or generate them from a configuration management system.

The configuration file has YAML-compatible format. The basic format of the YAML configuration file is as follows:

---
Db: "/volumes/data"
Log: "/esdb/logs"

TIP

You need to use the three dashes and spacing in your YAML file.

The default configuration file name is eventstore.conf. It is located in /etc/eventstore/ on Linux and the server installation directory on Windows. You can either change this file or create another file and instruct EventStoreDB to use it.

To tell the EventStoreDB server to use a different configuration file, you pass the file path on the command line with --config=filename, or use the CONFIG environment variable.

Environment variables

You can also set all arguments with environment variables. All variables are prefixed with EVENTSTORE_ and normally follow the pattern EVENTSTORE_{option}. For example, setting the EVENTSTORE_LOG variable would instruct the server to use a custom location for log files.

Environment variables override all the options specified in configuration files.

Command line

You can also override options from both configuration files and environment variables using the command line.

For example, starting EventStoreDB with the --log option will override the default log files location:

eventstored --log /tmp/eventstore/logs
EventStore.ClusterNode.exe --log C:\Temp\EventStore\Logs

Testing the configuration

If more than one method is used to configure the server, it might be hard to find out what the effective configuration will be when the server starts. To help to find out just that, you can use the --what-if option.

When you run EventStoreDB with this option, it will print out the effective configuration applied from all available sources (default and custom configuration file, environment variables and command line parameters) and print it out to the console.

Click here to see a WhatIf example
$ eventstored --what-if
[  160, 1,19:34:03.987,INF]
"ES VERSION:"             "22.6.0.0" ("tags/oss-v22.6.0"/"bad9b1b07", "Fri, 5 Aug 2022 15:52:56 +0200")
[  160, 1,19:34:04.000,INF] "OS ARCHITECTURE:"        X64
[  160, 1,19:34:04.008,INF] "OS:"                     Linux ("Unix 5.10.102.1")
[  160, 1,19:34:04.009,INF] "RUNTIME:"                ".NET 5.0.17/6a9841436" (64-bit)
[  160, 1,19:34:04.009,INF] "GC:"                     "3 GENERATIONS" "IsServerGC: False" "Latency Mode: Interactive"
[  160, 1,19:34:04.009,INF] "LOGS:"                   "/var/log/eventstore"
[  160, 1,19:34:04.037,INF] MODIFIED OPTIONS:

     WHAT IF:                                 true (Command Line)

DEFAULT OPTIONS:

     ADVERTISE HOST TO CLIENT AS:             <empty> (<DEFAULT>)
     ADVERTISE HTTP PORT TO CLIENT AS:        0 (<DEFAULT>)
     ADVERTISE TCP PORT TO CLIENT AS:         0 (<DEFAULT>)
     ALWAYS KEEP SCAVENGED:                   False (<DEFAULT>)
     AUTHENTICATION CONFIG:                   <empty> (<DEFAULT>)
     AUTHENTICATION TYPE:                     internal (<DEFAULT>)
     AUTHORIZATION CONFIG:                    <empty> (<DEFAULT>)
     AUTHORIZATION TYPE:                      internal (<DEFAULT>)
     CACHED CHUNKS:                           -1 (<DEFAULT>)
     CERTIFICATE FILE:                        <empty> (<DEFAULT>)
     CERTIFICATE PASSWORD:                    <empty> (<DEFAULT>)
     CERTIFICATE PRIVATE KEY FILE:            <empty> (<DEFAULT>)
     CERTIFICATE RESERVED NODE COMMON NAME:   eventstoredb-node (<DEFAULT>)
     CERTIFICATE STORE LOCATION:              <empty> (<DEFAULT>)
     CERTIFICATE STORE NAME:                  <empty> (<DEFAULT>)
     CERTIFICATE SUBJECT NAME:                <empty> (<DEFAULT>)
     CERTIFICATE THUMBPRINT:                  <empty> (<DEFAULT>)
     CHUNK INITIAL READER COUNT:              5 (<DEFAULT>)
     CHUNK SIZE:                              268435456 (<DEFAULT>)
     CHUNKS CACHE SIZE:                       536871424 (<DEFAULT>)
     CLUSTER DNS:                             fake.dns (<DEFAULT>)
     CLUSTER GOSSIP PORT:                     2113 (<DEFAULT>)
     CLUSTER SIZE:                            1 (<DEFAULT>)
     COMMIT ACK COUNT:                        1 (<DEFAULT>)
     COMMIT COUNT:                            -1 (<DEFAULT>)
     COMMIT TIMEOUT MS:                       2000 (<DEFAULT>)
     CONFIG:                                  /etc/eventstore/eventstore.conf (<DEFAULT>)
     CONNECTION PENDING SEND BYTES THRESHOLD: 10485760 (<DEFAULT>)
     CONNECTION QUEUE SIZE THRESHOLD:         50000 (<DEFAULT>)
     DB:                                      /var/lib/eventstore (<DEFAULT>)
     DB LOG FORMAT:                           V2 (<DEFAULT>)
     DEAD MEMBER REMOVAL PERIOD SEC:          1800 (<DEFAULT>)
     DISABLE ADMIN UI:                        False (<DEFAULT>)
     DISABLE EXTERNAL TCP TLS:                False (<DEFAULT>)
     DISABLE FIRST LEVEL HTTP AUTHORIZATION:  False (<DEFAULT>)
     DISABLE GOSSIP ON HTTP:                  False (<DEFAULT>)
     DISABLE HTTP CACHING:                    False (<DEFAULT>)
     DISABLE INTERNAL TCP TLS:                False (<DEFAULT>)
     DISABLE LOG FILE:                        False (<DEFAULT>)
     DISABLE SCAVENGE MERGING:                False (<DEFAULT>)
     DISABLE STATS ON HTTP:                   False (<DEFAULT>)
     DISCOVER VIA DNS:                        True (<DEFAULT>)
     ENABLE ATOM PUB OVER HTTP:               False (<DEFAULT>)
     ENABLE EXTERNAL TCP:                     False (<DEFAULT>)
     ENABLE HISTOGRAMS:                       False (<DEFAULT>)
     ENABLE TRUSTED AUTH:                     False (<DEFAULT>)
     EXT HOST ADVERTISE AS:                   <empty> (<DEFAULT>)
     EXT IP:                                  127.0.0.1 (<DEFAULT>)
     EXT TCP HEARTBEAT INTERVAL:              2000 (<DEFAULT>)
     EXT TCP HEARTBEAT TIMEOUT:               1000 (<DEFAULT>)
     EXT TCP PORT:                            1113 (<DEFAULT>)
     EXT TCP PORT ADVERTISE AS:               0 (<DEFAULT>)
     FAULT OUT OF ORDER PROJECTIONS:          False (<DEFAULT>)
     GOSSIP ALLOWED DIFFERENCE MS:            60000 (<DEFAULT>)
     GOSSIP INTERVAL MS:                      2000 (<DEFAULT>)
     GOSSIP ON SINGLE NODE:                   <empty> (<DEFAULT>)
     GOSSIP SEED:                             <empty> (<DEFAULT>)
     GOSSIP TIMEOUT MS:                       2500 (<DEFAULT>)
     HASH COLLISION READ LIMIT:               100 (<DEFAULT>)
     HELP:                                    False (<DEFAULT>)
     HTTP PORT:                               2113 (<DEFAULT>)
     HTTP PORT ADVERTISE AS:                  0 (<DEFAULT>)
     INDEX:                                   <empty> (<DEFAULT>)
     INDEX CACHE DEPTH:                       16 (<DEFAULT>)
     INDEX CACHE SIZE:                        0 (<DEFAULT>)
     INITIALIZATION THREADS:                  1 (<DEFAULT>)
     INSECURE:                                False (<DEFAULT>)
     INT HOST ADVERTISE AS:                   <empty> (<DEFAULT>)
     INT IP:                                  127.0.0.1 (<DEFAULT>)
     INT TCP HEARTBEAT INTERVAL:              700 (<DEFAULT>)
     INT TCP HEARTBEAT TIMEOUT:               700 (<DEFAULT>)
     INT TCP PORT:                            1112 (<DEFAULT>)
     INT TCP PORT ADVERTISE AS:               0 (<DEFAULT>)
     KEEP ALIVE INTERVAL:                     10000 (<DEFAULT>)
     KEEP ALIVE TIMEOUT:                      10000 (<DEFAULT>)
     LEADER ELECTION TIMEOUT MS:              1000 (<DEFAULT>)
     LOG:                                     /var/log/eventstore (<DEFAULT>)
     LOG CONFIG:                              logconfig.json (<DEFAULT>)
     LOG CONSOLE FORMAT:                      Plain (<DEFAULT>)
     LOG FAILED AUTHENTICATION ATTEMPTS:      False (<DEFAULT>)
     LOG FILE INTERVAL:                       Day (<DEFAULT>)
     LOG FILE RETENTION COUNT:                31 (<DEFAULT>)
     LOG FILE SIZE:                           1073741824 (<DEFAULT>)
     LOG HTTP REQUESTS:                       False (<DEFAULT>)
     LOG LEVEL:                               Default (<DEFAULT>)
     MAX APPEND SIZE:                         1048576 (<DEFAULT>)
     MAX AUTO MERGE INDEX LEVEL:              2147483647 (<DEFAULT>)
     MAX MEM TABLE SIZE:                      1000000 (<DEFAULT>)
     MAX TRUNCATION:                          268435456 (<DEFAULT>)
     MEM DB:                                  False (<DEFAULT>)
     MIN FLUSH DELAY MS:                      2 (<DEFAULT>)
     NODE PRIORITY:                           0 (<DEFAULT>)
     OPTIMIZE INDEX MERGE:                    False (<DEFAULT>)
     PREPARE ACK COUNT:                       1 (<DEFAULT>)
     PREPARE COUNT:                           -1 (<DEFAULT>)
     PREPARE TIMEOUT MS:                      2000 (<DEFAULT>)
     PROJECTION COMPILATION TIMEOUT:          500 (<DEFAULT>)
     PROJECTION EXECUTION TIMEOUT:            250 (<DEFAULT>)
     PROJECTION THREADS:                      3 (<DEFAULT>)
     PROJECTIONS QUERY EXPIRY:                5 (<DEFAULT>)
     QUORUM SIZE:                             1 (<DEFAULT>)
     READ ONLY REPLICA:                       False (<DEFAULT>)
     READER THREADS COUNT:                    0 (<DEFAULT>)
     REDUCE FILE CACHE PRESSURE:              False (<DEFAULT>)
     RUN PROJECTIONS:                         None (<DEFAULT>)
     SCAVENGE HISTORY MAX AGE:                30 (<DEFAULT>)
     SKIP DB VERIFY:                          False (<DEFAULT>)
     SKIP INDEX SCAN ON READS:                False (<DEFAULT>)
     SKIP INDEX VERIFY:                       False (<DEFAULT>)
     START STANDARD PROJECTIONS:              False (<DEFAULT>)
     STATS PERIOD SEC:                        30 (<DEFAULT>)
     STATS STORAGE:                           File (<DEFAULT>)
     STREAM EXISTENCE FILTER SIZE:            256000000 (<DEFAULT>)
     STREAM INFO CACHE CAPACITY:              0 (<DEFAULT>)
     TRUSTED ROOT CERTIFICATE STORE LOCATION: <empty> (<DEFAULT>)
     TRUSTED ROOT CERTIFICATE STORE NAME:     <empty> (<DEFAULT>)
     TRUSTED ROOT CERTIFICATE SUBJECT NAME:   <empty> (<DEFAULT>)
     TRUSTED ROOT CERTIFICATE THUMBPRINT:     <empty> (<DEFAULT>)
     TRUSTED ROOT CERTIFICATES PATH:          <empty> (<DEFAULT>)
     UNBUFFERED:                              False (<DEFAULT>)
     UNSAFE ALLOW SURPLUS NODES:              False (<DEFAULT>)
     UNSAFE DISABLE FLUSH TO DISK:            False (<DEFAULT>)
     UNSAFE IGNORE HARD DELETE:               False (<DEFAULT>)
     USE INDEX BLOOM FILTERS:                 True (<DEFAULT>)
     VERSION:                                 False (<DEFAULT>)
     WORKER THREADS:                          0 (<DEFAULT>)
     WRITE STATS TO DB:                       False (<DEFAULT>)
     WRITE THROUGH:                           False (<DEFAULT>)
     WRITE TIMEOUT MS:                        2000 (<DEFAULT>)
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NOTE

Version 21.6 introduced a stricter configuration check: the server will not start when an unknown configuration options is passed in either the configuration file, environment variable or command line.

E.g: the following will prevent the server from starting:

  • --UnknownConfig on the command line
  • EVENTSTORE_UnknownConfig through environment variable
  • UnknownConfig: value in the config file

And will output on stdout only: Error while parsing options: The option UnknownConfig is not a known option. (Parameter 'UnknownConfig').

Autoconfigured options

Some options are configured at startup to make better use of the available resources on larger instances or machines.

These options are StreamInfoCacheCapacity, ReaderThreadsCount, and WorkerThreads.

StreamInfoCacheCapacity

This option sets the maximum number of entries to keep in the stream info cache. This is the lookup that contains the information of any stream that has recently been read or written to. Having entries in this cache significantly improves write and read performance to cached streams on larger databases.

The cache is configured at startup based on the available free memory at the time. If there is 4gb or more available, it will be configured to take at most 75% of the remaining memory, otherwise it will take at most 50%. The minimum that it can be set to is 100,000 entries.

FormatSyntax
Command line--stream-info-cache-capacity
YAMLStreamInfoCacheCapacity
Environment variableSTREAM_INFO_CACHE_CAPACITY

The option is set to 0 by default, which enables autoconfiguration. The default on previous versions of EventStoreDb was 100,000 entries.

ReaderThreadsCount

This option configures the number of reader threads available to EventStoreDb. Having more reader threads allows more concurrent reads to be processed.

The reader threads count will be set at startup to twice the number of available processors, with a minimum of 4 and a maximum of 16 threads.

FormatSyntax
Command line--reader-threads-count
YAMLReaderThreadsCount
Environment variableREADER_THREADS_COUNT

The option is set to 0 by default, which enables autoconfiguration. The default on previous versions of EventStoreDb was 4 threads.

WARNING

Increasing the reader threads count too high can cause read timeouts if your disk cannot handle the increased load.

WorkerThreads

The WorkerThreads option configures the number of threads available to the pool of worker services.

At startup the number of worker threads will be set to 10 if there are more than 4 reader threads. Otherwise, it will be set to have 5 threads available.

FormatSyntax
Command line--worker-threads
YAMLWorkerThreads
Environment variableWORKER_THREADS

The option is set to 0 by default, which enables autoconfiguration. The default on previous versions of EventStoreDb was 5 threads.