How to run TeamCity on 64-bit JVM

The way I made it work (TeamCity 8, Windows server 2008 r2):

• Install the 64-bit JRE on the target machine, now there are two ways to do this

• A -> If you are using the Teamcity bundled JRE, replace the JRE folder ([TC Server folder]\JRE) with the JRE folder in the newly installed JRE x64 - You have to shut down the TC server service (along with all java.exe*32 services that might also use this JRE)

• B -> Change the TeamCity Internal properties, to point to newly installed JRE x64 (see documentation for TC version 8, TC version 9 can be found here):

  java.home=C\:\\<JRE x64 install folder>\\jrejava.ext.dirs=C\:\\<JRE x64 install folder>\\jre\\lib\\ext\;C\:\\Windows\\Sun\\Java\\lib\\ext java.library.path=C\:\\<JRE x64 install folder>\\jre\\bin\;C\:\\Windows\\Sun\\Java\\bin\;C\:\\Windows\\system32\;C\:\\Windows\;C\:\\local\\Oracle\\clients\\112_64\\bin\;C\:\\local\\Oracle… 

• An alternative to point B would be to change Environment variable JAVA_HOME, it`s more simple, but it requires a Windows server restart after that

• If you run the TC Server service now, it should run as a 64-bit Java process (chceck via PID in task manager) :

• Don`t be alarmed if the server does not start up throwing an error :

   Error: SQL error when doing: Connecting to MSSQL: I/O Error: SSO Failed: Native SSPI library not loaded. Check the java.library.path system property 

• Download JTDS - 1.3.1 (http://sourceforge.net/projects/jtds/files/jtds/1.3.1/) and install it

• Take the ntlmauth.dll file from [JTDS-1.3.1 install folder]/x64/SSO folder and replace the one in [TC Server folder]\bin

• The TC server should now run fine as 64 bit Java process

• You can increase the memory allocation (as that is the whole point of the upgrade) now on the server as described here : https://confluence.jetbrains.com/display/TCD8/Installing+and+Configuring+the+TeamCity+Server#InstallingandConfiguringtheTeamCityServer-SettingUpMemorysettingsforTeamCityServer

The snippet from the updated question had a link in the original, pointing to the instructions on Java update for TeamCity server in TeamCity online doc.

Basically, the instructions vary based on the TeamCity distribution used and way of launching the server.

If your intent is to increase the memory for the TeamCity server, please make sure to read through the corresponding section on the same doc page.

Yet one more note: recent TeamCity versions perform Git fetch in a separate process and Git-related memory issues during fetch might require fine-tuning of the corresponding options.

"So I guess I need to copy some files into the /jre folder?"

No. You install a 64 bit JRE, and update the relevant setting to point at the 64-bit install's JRE.

Don't copy stuff from one JRE installation into another. You will break things!