Reducing memory usage

Default MaxRAM Setting

One of the settings java virtual machines use to calibrate how much physical memory to reserve at startup is MaxRAM, and there is a good chance your JVM thinks it has more RAM to use than is installed on your machine. To check the default MaxRAM setting, run this java 'version' command:

   java -XX:+UnlockDiagnosticVMOptions -XX:+PrintFlagsFinal -version | grep MaxRAM

Look for the default MaxRAM setting in the output; this machine says

   367: uint64_t MaxRAM                                   = 137438953472                           {pd product} {default}

meaning my OpenJDK 11 JVM's MaxRAM setting is 128 GB, on a machine with only 16 GB RAM.

Experiments have shown starting Bisq with a 4g (GB) MaxRAM setting reduces resident memory consumption by more than 50% when starting a clean Bisq installation -- with an empty data directory.

Setting MaxRAM to 2g reduces resident memory usage even more, but setting it any lower (1536m) will result in an OutOfMemoryError and crash the app.

As of version 1.2.7, Bisq starts up with a MaxRAM setting of 4g (GB). If you are using Bisq v1.2.6 or older, consider upgrading to the latest version to reduce Bisq's RAM usage.