> From: Christopher Schultz [mailto:[EMAIL PROTECTED] > Subject: Re: [OT]Re: Is better one or more Tomcat instances > per machine > > Hmm.... perhaps I have a virtual memory limit. I have 1GB > of physical RAM. While allocating a 3GB heap is pretty > stupid for me, I still ought to be able to do it.
If your OS will allow, yes you should. You may need to increase your swap file space, and you may burn out your hard drive thrashing pages in and out. > My ulimit man page sucks. Anyone know how to change the virtual memory > limits on Linux 2.6? Here's a link for SUSE: http://en.opensuse.org/SDB:Ulimit_for_Protection_Against_%22Out_of_memor y%22 > If the heap can grow and shrink, then how can the VM hope to > get one bigass memory chunk for the heap? The JVM reserves - but does not commit - the -Xmx size during initialization. If that's not available, the JVM won't start. Once allocated, commits and decommits occur to expand and shrink the in-use size. > does the VM freeze everything and relocate the heap to > another section of memory? No, since the maximum size is allocated from the beginning. > The fact that the boundaries can be moved really complicates things. Agreed. I think HotSpot has gone a bit overboard in this regard. > Still, the only remaining reason that 2GB+ wouldn't work is > because of a (potential) 2GB contiguous memory allocation > restriction. I see no such restriction in the malloc or brk > man pages on my system. What gives? Those are typically generic descriptions aimed at application programmers. What we're discussing here is OS internals, and you'll rarely see those documented anywhere. If you're lucky, the OS vendor will have such limitiations squirreled away in some appendix to its installation guide. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
