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* [Doc] Document the usage of LS_JAVA_OPTS environment variable
Co-authored-by: Rob Bavey <rob.bavey@elastic.co>
(cherry picked from commit 9242105c3c)
Co-authored-by: Andrea Selva <selva.andre@gmail.com>
118 lines
3.8 KiB
Text
118 lines
3.8 KiB
Text
[[jvm-settings]]
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=== JVM settings
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Configure JVM settings in the `jvm.options` <<settings-files,settings file>>. JVM settings can also be set via the <<ls-java-opts, `LS_JAVA_OPTS`>> environment variable.
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This file contains a line-delimited list of JVM arguments following a special syntax:
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* lines consisting of whitespace only are ignored
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* lines beginning with `#` are treated as comments and are ignored
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+
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[source,text]
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-------------------------------------
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# this is a comment
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-------------------------------------
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* lines beginning with a `-` are treated as a JVM option that applies
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independent of the version of the JVM
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+
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[source,text]
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-------------------------------------
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-Xmx2g
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-------------------------------------
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* lines beginning with a number followed by a `:` followed by a `-` are treated
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as a JVM option that applies only if the version of the JVM matches the number
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+
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[source,text]
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-------------------------------------
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8:-Xmx2g
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-------------------------------------
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* lines beginning with a number followed by a `-` followed by a `:` are treated
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as a JVM option that applies only if the version of the JVM is greater than or
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equal to the number
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+
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[source,text]
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-------------------------------------
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8-:-Xmx2g
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-------------------------------------
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* lines beginning with a number followed by a `-` followed by a number followed
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by a `:` are treated as a JVM option that applies only if the version of the
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JVM falls in the inclusive range of the two numbers
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+
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[source,text]
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-------------------------------------
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8-9:-Xmx2g
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-------------------------------------
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* all other lines are rejected
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[[heap-size]]
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==== Setting the JVM heap size
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Here are some tips for adjusting the JVM heap size:
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// tag::heap-size-tips[]
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* The recommended heap size for typical ingestion scenarios should be no
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less than 4GB and no more than 8GB.
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* CPU utilization can increase unnecessarily if the heap size is too low,
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resulting in the JVM constantly garbage collecting. You can check for this issue
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by doubling the heap size to see if performance improves.
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* Do not increase the heap size past the amount of physical memory. Some memory
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must be left to run the OS and other processes. As a general guideline for most
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installations, don't exceed 50-75% of physical memory. The more memory you have,
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the higher percentage you can use.
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* Set the minimum (Xms) and maximum (Xmx) heap allocation size to the same
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value to prevent the heap from resizing at runtime, which is a very costly
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process.
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* You can make more accurate measurements of the JVM heap by using either the
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`jmap` command line utility distributed with Java or by using VisualVM. For more
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info, see <<profiling-the-heap>>.
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// end::heap-size-tips[]
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[[stacks-size]]
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==== Setting the JVM stack size
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Large configurations may require additional JVM stack memory.
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If you see a stack overflow error, try increasing the JVM stack size.
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Add an entry similar to this one in the `jvm.options`
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<<settings-files,settings file>>:
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[source,sh]
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-----
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-Xss4M
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-----
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Note that the default stack size is different per platform and per OS
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flavor. You can find out what the default is by running:
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[source,sh]
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-----
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java -XX:+PrintFlagsFinal -version | grep ThreadStackSize
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-----
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Depending on the default stack size, start by multiplying by 4x, then 8x, and
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then 16x until the overflow error resolves.
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[[ls-java-opts]]
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==== Using `LS_JAVA_OPTS`
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The `LS_JAVA_OPTS` environment variable can also be used to override JVM settings in the `jvm.options` file <<settings-files,settings file>>.
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The content of this variable is additive to options configured in the `jvm.options` file, and will override any settings that exist in both places.
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For example to set a different locale to launch {ls} instance:
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[source,sh]
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-----
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LS_JAVA_OPTS="-Duser.country=DE -Duser.language=de" bin/logstash -e 'input { stdin { codec => json } }'
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-----
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