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Diffstat (limited to 'docs')
-rw-r--r-- | docs/configuration.md | 31 | ||||
-rw-r--r-- | docs/ec2-scripts.md | 5 | ||||
-rw-r--r-- | docs/tuning.md | 6 |
3 files changed, 25 insertions, 17 deletions
diff --git a/docs/configuration.md b/docs/configuration.md index 2de512f896..ae61769e31 100644 --- a/docs/configuration.md +++ b/docs/configuration.md @@ -25,23 +25,25 @@ Inside `spark-env.sh`, you *must* set at least the following two variables: * `SCALA_HOME`, to point to your Scala installation. * `MESOS_NATIVE_LIBRARY`, if you are [running on a Mesos cluster](running-on-mesos.html). -In addition, there are four other variables that control execution. These can be set *either in `spark-env.sh` -or in each job's driver program*, because they will automatically be propagated to workers from the driver. -For a multi-user environment, we recommend setting the in the driver program instead of `spark-env.sh`, so -that different user jobs can use different amounts of memory, JVM options, etc. +In addition, there are four other variables that control execution. These should be set *in the environment that +launches the job's driver program* instead of `spark-env.sh`, because they will be automatically propagated to +workers. Setting these per-job instead of in `spark-env.sh` ensures that different jobs can have different settings +for these variables. -* `SPARK_MEM`, to set the amount of memory used per node (this should be in the same format as the - JVM's -Xmx option, e.g. `300m` or `1g`) * `SPARK_JAVA_OPTS`, to add JVM options. This includes any system properties that you'd like to pass with `-D`. * `SPARK_CLASSPATH`, to add elements to Spark's classpath. * `SPARK_LIBRARY_PATH`, to add search directories for native libraries. +* `SPARK_MEM`, to set the amount of memory used per node. This should be in the same format as the + JVM's -Xmx option, e.g. `300m` or `1g`. Note that this option will soon be deprecated in favor of + the `spark.executor.memory` system property, so we recommend using that in new code. -Note that if you do set these in `spark-env.sh`, they will override the values set by user programs, which -is undesirable; you can choose to have `spark-env.sh` set them only if the user program hasn't, as follows: +Beware that if you do set these variables in `spark-env.sh`, they will override the values set by user programs, +which is undesirable; if you prefer, you can choose to have `spark-env.sh` set them only if the user program +hasn't, as follows: {% highlight bash %} -if [ -z "$SPARK_MEM" ] ; then - SPARK_MEM="1g" +if [ -z "$SPARK_JAVA_OPTS" ] ; then + SPARK_JAVA_OPTS="-verbose:gc" fi {% endhighlight %} @@ -55,11 +57,18 @@ val sc = new SparkContext(...) {% endhighlight %} Most of the configurable system properties control internal settings that have reasonable default values. However, -there are at least four properties that you will commonly want to control: +there are at least five properties that you will commonly want to control: <table class="table"> <tr><th>Property Name</th><th>Default</th><th>Meaning</th></tr> <tr> + <td>spark.executor.memory</td> + <td>512m</td> + <td> + Amount of memory to use per executor process, in the same format as JVM memory strings (e.g. `512m`, `2g`). + </td> +</tr> +<tr> <td>spark.serializer</td> <td>spark.JavaSerializer</td> <td> diff --git a/docs/ec2-scripts.md b/docs/ec2-scripts.md index dc57035eba..eab8a0ff20 100644 --- a/docs/ec2-scripts.md +++ b/docs/ec2-scripts.md @@ -106,9 +106,8 @@ permissions on your private key file, you can run `launch` with the # Configuration You can edit `/root/spark/conf/spark-env.sh` on each machine to set Spark configuration options, such -as JVM options and, most crucially, the amount of memory to use per machine (`SPARK_MEM`). -This file needs to be copied to **every machine** to reflect the change. The easiest way to do this -is to use a script we provide called `copy-dir`. First edit your `spark-env.sh` file on the master, +as JVM options. This file needs to be copied to **every machine** to reflect the change. The easiest way to +do this is to use a script we provide called `copy-dir`. First edit your `spark-env.sh` file on the master, then run `~/spark-ec2/copy-dir /root/spark/conf` to RSYNC it to all the workers. The [configuration guide](configuration.html) describes the available configuration options. diff --git a/docs/tuning.md b/docs/tuning.md index 32c7ab86e9..5ffca54481 100644 --- a/docs/tuning.md +++ b/docs/tuning.md @@ -157,9 +157,9 @@ their work directories), *not* on your driver program. **Cache Size Tuning** -One important configuration parameter for GC is the amount of memory that should be used for -caching RDDs. By default, Spark uses 66% of the configured memory (`SPARK_MEM`) to cache RDDs. This means that - 33% of memory is available for any objects created during task execution. +One important configuration parameter for GC is the amount of memory that should be used for caching RDDs. +By default, Spark uses 66% of the configured executor memory (`spark.executor.memory` or `SPARK_MEM`) to +cache RDDs. This means that 33% of memory is available for any objects created during task execution. In case your tasks slow down and you find that your JVM is garbage-collecting frequently or running out of memory, lowering this value will help reduce the memory consumption. To change this to say 50%, you can call |