= Distributed James Server &mdash; jvm.properties
:navtitle: jvm.properties

This file may contain any additional system properties for tweaking JVM execution. When you normally would add a command line option `-Dmy.property=whatever`, you can put it in this file as `my.property=whatever` instead. These properties will be added as system properties on server start.

Note that in some rare cases this might not work,
when a property affects very early JVM start behaviour.

For testing purposes, you may specify a different file path via the command line option `-Dextra.props=/some/other/jvm.properties`.

== Control the threshold memory
This governs the threshold MimeMessageInputStreamSource relies on for storing MimeMessage content on disk.

In `jvm.properties`
----
james.message.memory.threshold=12K
----

(Optional). String (size, integer + size units, example: `12 KIB`, supported units are bytes KIB MIB GIB TIB). Defaults to 100KIB.

== Enable the copy of message in memory
Should MimeMessageWrapper use a copy of the message in memory? Or should bigger message exceeding james.message.memory.threshold
be copied to temporary files?

----
james.message.usememorycopy=true
----

Optional. Boolean. Defaults to false. Recommended value is false.

== Running resource leak detection
It is used to detect a resource not be disposed of before it's garbage-collected.

In `jvm.properties`
----
james.lifecycle.leak.detection.mode=advanced
----

Allowed mode values are: none, simple, advanced, testing

The purpose of each mode is introduced in `config-system.xml`

== Disabling host information in protocol MDC logging context

Should we add the host in the MDC logging context for incoming IMAP, SMTP, POP3? Doing so, a DNS resolution
is attempted for each incoming connection, which can be costly. Remote IP is always added to the logging context.


In `jvm.properties`
----
james.protocols.mdc.hostname=false
----

Optional. Boolean. Defaults to true.

== Change the encoding type used for the blobId

By default, the blobId is encoded in base64 url. The property `james.blob.id.hash.encoding` allows to change the encoding type.
The support value are: base16, hex, base32, base32Hex, base64, base64Url.

Ex in `jvm.properties`
----
james.blob.id.hash.encoding=base16
----

Optional. String. Defaults to base64Url.

== JMAP Quota draft compatibility

Some JMAP clients depend on the JMAP Quota draft specifications. The property `james.jmap.quota.draft.compatibility` allows
to enable JMAP Quota draft compatibility for those clients and allow them a time window to adapt to the RFC-9245 JMAP Quota.

Optional. Boolean. Default to false.

Ex in `jvm.properties`
----
james.jmap.quota.draft.compatibility=true
----
To enable the compatibility.

== Enable S3 metrics

James supports extracting some S3 client-level metrics e.g. number of connections being used, time to acquire an S3 connection, total time to finish a S3 request...

The property `james.s3.metrics.enabled` allows to enable S3 metrics collection. Please pay attention that enable this
would impact a bit on S3 performance.

Optional. Boolean. Default to true.

Ex in `jvm.properties`
----
james.s3.metrics.enabled=false
----
To disable the S3 metrics.