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[Marcinnnn]

Hi,


I have a problem cause I can't find any info about max memory for single process in Java for x86_64 (alias amd64) architecture. Man java in Linux with x86_64 says that there is a limit 2000M for 32 bit systems. It looks for me that default max is also 2000M cause on x86_64 default is 32 bit mode but what if I switch Java to 64 bit mode? Is it safe for big application? Is it stable? And what is the max memo limit? I really need some good documentation for that and I can't find it.

I have also little problem with tomcat memo consuming. When it got in example -Xmx512M option and I start tomcat in Linux ps aux gives me 3 processes with this options. Is it means that I gave him 3*(512M) or just 512M and other are some kind of subprocesses?


Thanks for help in advance! :-)

[Alexander]

A 64 bit OS running in Long mode can theoretically allocate roughly 4PB of address space, so I do not think that is a problem.
Java Tuning White Paper

When there are multiple instances of a server, they are likely sharing the same memory for shared libraries and are not really taking up as much as they appear in top, try to allocate 1G of memory to a Tomcat server and use free -m (remember to use the +/- buffers line not the top one) to compare before and after if they really are taking that up, I would assume they aren't (and only use it when needed).