Revelation 1.8 server won't start ( invalid initial heap size: -xms )



I’ve been hosting a FTB Revelation server for my friends and I for awhile now, and recently updated to 1.8 and went to update the server as well. I began getting an error every time I launched the serverstart batch file that reads “invalid initial heap size: -xms”. I did a little bit of digging and found that it means that the amount of ram I have it set to use is invalid, and so I began trying to set the max_ram to different values (including using 3072m which is the amount I was running the 1.6 server with) and got no results. Usually I can fix these kinds of problems but this one has me stumped.

Thank you for your time!


share a log or a screen shot


I had this problem, initially, too. Easy fix. The 1.8 settings file doesn’t have some of the parameters you need for Java 8. They probably tested the pack on Java 9? Not sure.

Compare your 1.6 “settings.bat” to the 1.8 “settings.bat” and re-add the missing bits.


oh yes… this problem may appear more often…
After deleting MIN_RAM out of settings.bat the ftb team forgot to edit the initial startup line in ServerStart.bat and instead just edited the restart line… So this is a bit more than just an annoying message like “-XX:PermSize” is deprecated for Java 8 (or sth like that) So %MIN_RAM% is emptry and the Parameter -Xms are missing the size argument.
It must match the syntax: -XmsNX ∀N,X : N∈ℕ ∧ (16|N ∨ X∈{K,M,G})

I saw this but forget about it :sweat_smile: I always edited settings.bat & ServerStart.bat myself.
Do one of this:

  • Just delete -Xms%MIN_RAM% out of the startup lines (java -server …) in ServerStart.bat
    I think Xms is optional in Java 8… If not, you need to do this:

  • settings.bat: add the following set
    REM Your preferred minimal RAM usage (assert MIN_RAM ≤ MAX_RAM !)
    set MIN_RAM=2G
    ServerStart.bat: change BOTH lines beginning with “java -server …”
    java -server -Xms%MIN_RAM% -Xmx%MAX_RAM% %JAVA_PARAMETERS% -jar %FORGEJAR% nogui


I also had this problem. I fixed it by:

Going to the Java Website
Clicking "All Java Downloads"
And then downloading the one labeled "Windows Offline (64-bit)"