NetWorker: How to change the java heap size for the NetWorker Management Console (NMC)

The NetWorker Management Console (NMC) uses a Java Runtime on the host accessing the console. The console uses the file gconsole.jnlp, which it downloads from the NMC server. This file defines Java memory limits for the host accessing the NMC. The default memory limit is 2 GB. In some scenarios, you may observe "running out of memory" errors in the NMC, even though the host accessing the NMC still has sufficient memory available. This happens when the NMC is nearing the Java heap limit for the NMC. This is expected behavior when performing some operations in the NMC, particularly in larger environments, or environments with a lot of data. 

The Java heap size may be changed from the default NMC value to accommodate various environment configurations.  
 

In the following example, the java heap size is increased on the NMC from 2 GB (-Xmx2048m) to 4 GB (-Xmx4096m) on the NetWorker Management Console Server. The new value applies to any NetWorker Management Console workstations connecting to the NetWorker Management Console Server.

1. Open the gconsole.jnlp file on the NetWorker Management Console Server.

• • Default Linux: /opt/lgtonmc/web/gconsole.jnlp
  • Default Windows: C:\Program Files\EMC NetWorker\Management\GST\web\gconsole.jnlp 

2. Change the line for the Java heap memory max size:
   1. NetWorker 19.12.x and prior

• • Existing: <j2se version="1.8+"  java-vm-args="-XX:+IgnoreUnrecognizedVMOptions --add-modules=java.se.ee -Xms256m -Xmx2048m"/>
  • Changed: <j2se version="1.8+"  java-vm-args="-XX:+IgnoreUnrecognizedVMOptions --add-modules=java.se.ee -Xms256m -Xmx4096m"/>

1. 2. NetWorker 19.13.x and later:

• • Existing: <j2se version="1.8+"  java-vm-args="-Djava.locale.providers=COMPAT"/>
  • Changed: <j2se version="1.8+"  java-vm-args="-Djava.locale.providers=COMPAT" initial-heap-size="512M" max-heap-size="4096M"/>

3. Restart the NMC services.

• • Linux: systemctl restart gst
  • Windows (PowerShell syntax): net stop gstd ; net start gstd

4. From the NMC workstation (host accessing the NMC), clear the Java cache. The following articles apply for NetWorker Runtime Environment (NRE):

• • NetWorker 19.12.x (and prior): NRE 8.x: How to clear Java Cache, enable Java Console and Debugging.
  • NetWorker 19.13.x (and later): NRE 17.x: How to Clear Java Cache, Enable Java Console, and Debugging

5. Launch the NMC.

Troubleshooting:

To check the settings applied and heap usage of a currently active NMC session, perform the following steps on the host accessing the NMC. These steps must be performed with the NMC open. 

1.  Open an Administrator Command-Prompt or PowerShell.
2. Change directory to your NetWorker Runtime Environment (NRE) java bin directory. For example:

   PS C:\Users\administrator.AMER> cd "C:\Program Files\NRE\java\"
   PS C:\Program Files\NRE\java> dir
   
   
       Directory: C:\Program Files\NRE\java
   
   
   Mode                 LastWriteTime         Length Name
   ----                 -------------         ------ ----
   d-----         1/19/2026   4:55 PM                jdk-17.0.17
   
   
   PS C:\Program Files\NRE\java> cd .\jdk-17.0.17\bin
   PS C:\Program Files\NRE\java\jdk-17.0.17\bin>

3. Get the PID of the java.exe process associated with OpenWebStart:

Get-CimInstance Win32_Process | Where-Object { $_.Name -like "*java*" } | Select-Object ProcessId, Name, CommandLine

PS C:\Program Files\NRE\java\jdk-17.0.17\bin> Get-CimInstance Win32_Process | Where-Object { $_.Name -like "*java*" } | Select-Object ProcessId, Name, CommandLine

ProcessId Name       CommandLine
--------- ----       -----------
     1352 javaws.exe "C:\Program Files\OpenWebStart\javaws.exe" "C:\Users\administrator.AMER\Downloads\gconsole.jnlp"
     7644 java.exe   "C:\Program Files\NRE\java\jdk-17.0.17\bin\java.exe" "-Xbootclasspath/a:C:\Program Files\OpenWebStart\openwebstart.jar" "-Dicedtea-web.bin.location=C:\Program Files\OpenWebStart\javaws" -Xms512M -Xmx2048M -Djava.locale.providers=COMPAT -Djava.util.Arrays.useLegacyMergeSort=true --add-reads=java.base=ALL-UNNAMED,java.desktop --add-reads=java.d...

4. Use jcmd to check the Java Virtual Machine (VM) settings and GC details:

.\jcmd.exe PID VM.flags
.\jcmd.exe PID GC.heap_info

PS C:\Program Files\NRE\java\jdk-17.0.17\bin> .\jcmd.exe 7644 VM.flags
7644:
-XX:CICompilerCount=2 -XX:ConcGCThreads=1 -XX:G1ConcRefinementThreads=2 -XX:G1EagerReclaimRemSetThreshold=8 -XX:G1HeapRegionSize=1048576 -XX:GCDrainStackTargetSize=64 -XX:InitialHeapSize=536870912 -XX:MarkStackSize=4194304 -XX:MaxHeapSize=2147483648 -XX:MaxNewSize=1287651328 -XX:MinHeapDeltaBytes=1048576 -XX:MinHeapSize=536870912 -XX:NonNMethodCodeHeapSize=5826188 -XX:NonProfiledCodeHeapSize=122916026 -XX:ProfiledCodeHeapSize=122916026 -XX:ReservedCodeCacheSize=251658240 -XX:+SegmentedCodeCache -XX:SoftMaxHeapSize=2147483648 -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseFastUnorderedTimeStamps -XX:+UseG1GC -XX:-UseLargePagesIndividualAllocation

PS C:\Program Files\NRE\java\jdk-17.0.17\bin> .\jcmd.exe 7644 GC.heap_info
7644:
 garbage-first heap   total 524288K, used 112318K [0x0000000080000000, 0x0000000100000000)
  region size 1024K, 103 young (105472K), 2 survivors (2048K)
 Metaspace       used 22772K, committed 23168K, reserved 1114112K
  class space    used 2530K, committed 2752K, reserved 1048576K