-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Abel,
On 1/15/2010 4:46 AM, Abel MacAdam wrote: > We manage several customers on VMWare systems. Their Tomcat installation is > used by a Content Management System written in Java. I have a question about > what happens with Tomcat when memory it has configured is not available when > necessary. > > Our Tomcat installations should use 500 MB (-Xmx516m). But when that memory > is not used, VMWare will take it away, and give it to other VMWares that are > in need of memory. This will not be a problem for a while. But at one moment > Tomcat may wish to use this memory, and VMWare will not be able to supply it > directly. What will happen in that case? This is a complicated question and depends entirely upon your environment. > F.W.I.W. We use Debian Linux in our installations. Tomcat gets 500 MB, total > memory is 2GB. Is Debian the host or the guest or both? Or, are you using VMWare Server or ESX or whatever they are calling their hypervisor-style virtualization these days? If you are running Linux as the host (in a guest/host configuration) then your guest OS might suffer from the Linux OOM killer. If you are running Linux as the guest (in a guest/host) configuration, or if you are running Linux as one of many peers (or whatever they're called) under a hypervisor, you may also suffer from the Linux OOM killer. Or, you might dip into swap space and start thrashing your machine. Or, VMWare might do the right thing and just re-allocate more memory to your VM and let you continue. None of this really have anything to do with Tomcat or the JVM. The best advice I can give is to stress-test your system to make sure that it behaves appropriately. Another option would be to ask VMWare, since they are the experts at their own product. - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAktQiCgACgkQ9CaO5/Lv0PCjRgCgww2x1eYDv/iFuyDQBH3q0DXU T6cAnjIn92Z6uvN6qI9uJ6G/yNy6H9BJ =FJnR -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
