On 17 February 2010 15:07, Jon Brisbin <jon.bris...@npcinternational.com> wrote: > We're running a dozen tcServer instances (Tomcat 6.0) on a VMware ESXi cloud > infrastructure. We haven't put vSphere in yet, but we're planning to. The > only thing I can say here is that there ARE differences between running > Tomcat on a VM and running it on dedicated hardware. I have problems with > things I know I'm doing right, but they just don't work the same on a VM. I > guess it has to do with the fact that the server is sometimes "swapped" out > if it's not in use. I think this causes issues, particularly with clustering, > which I have yet to make work in a way that I'm happy with. > > The big one that I noticed right away is that anything that uses /dev/random > will take forever to start. VMs have very little entropy in their pools > because they don't have any real hardware. This means stuff that uses > /dev/random for entropy (if it has security/SSL in it or is uses Random) will > take several minutes to start (usually 3-5 in our tests). > > When they run, they run great. We're seeing a great improvement in > performance running on VMware. It's just there seem to be a lot of little > issues that no one else seems to have. This means I either have no idea what > I'm doing (possible :) or things just run differently on VMs than they do on > real hardware.
VMWare did put out a white-paper about Java and VMWare:- http://www.vmware.com/resources/techresources/1087 I can't vouch for how much use it is though I'm afraid. You might consider switching to /dev/urandom for entropy if it's taking minutes to generate with /dev/random. Cheers, Phil. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
