Can we use a virtual machine (Machine A) to take the backup of another virtual machines snapshot(Machine B). If we can do it what setup should we make (in machine A). Can you give me a working example with some real virtualization techniques.Assumption is that both the virtual machines are running on some cloud virtual machine management services for example like ovirt
Although it is a general question, I think the feature you are really looking for is snapshots. I use a lot of cloud based VMs, most cloud provider offer you to snapshot your volumes, this is the preferred way to do backups in the cloud as it doesn't require you to stop or slow down your VM the back up is done at the disk level. Later on you can restore your backups by creating an image out of your disk snapshots and spinning a new VM with this image.
On the other hand if you really need to backup a running at the filesystem level, you can have a look at rsync on linux/unix hosts. For Windows sorry I don't have a clue...