VMWare - network applications

Question

I am developing a distributed file system using Java, I cannot give many details at this moment. I need to test some things on Linux, I will use WMWare server an install Linux inside a virtual machine. Is there any difference between the simulated network card and a real ethernet interface?

Answer 1

From the point of view of application code, no, there's no difference.

The only visible difference might be in performance - the speed of response and exact timings of things might be different, but you're talking microseconds.

There's so much general-purpose software that works flawlessly under VMs that the answer to almost every question of the form "Are VMs different from real machines?" at the application level is "No".

(Things might be different if you were talking about kernel-level driver software.)

Answer 2

I am developing a distributed file system ... I will use WMWare server an install Linux inside a virtual machine.

VMware is great for this sort of thing. There should be no difference except, as RichieHindle said, in performance, especially if you're planning to run multiple vms on the same server.

Use real hardware if you want usable performance benchmark results.

Java is it's own 'VM'... on top of a layer of virtualization in the guest OS... on top of VMware... on a virtual execution model CPU. Take a little virtualization here, add a little virtualization there, and pretty soon we're talking about some real abstraction!