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Estimating Heap Sizes

General Memory Guidelines

  • Minimum physical/RAM memory on the host 16GB for production use

  • Minimum heap ( -Xms ) must equal set maximum heap ( -Xmx )

  • Minimum heap size 8GB for production use

  • Minimum unallocated host physical/RAM memory should be no less than 1/3 of total physical RAM to allow space for OS, application binaries, and SCM integration

  • For heap >= 8GB recommend using G1GC garbage collector

Guidelines for Heap Sizing

These profiles help gauge the typical physical memory requirements needed for a dedicated server host running IQ Server.Due to the inherent complexities of use cases, one size does not fit all and this should only be interpreted as a guideline.

Profile Use Case

Physical/RAM Memory

Heap Settings


(no. of applications< 20)


-Xmx4g -Xms4g

Small team

(no. of applications <100)


-Xmx8g -Xms8g -XX:+UseG1GC

Medium team

(no. of applications <500)


-Xmx16g -Xms16g -XX:+UseG1GC

Large, enterprise

(no. of applications > 500)


Xmx24g -Xms24g -XX:+UseG1GC