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Read the difference b/w virtual and physical server
It says
The resources and components of a physical server are not shared between multiple users.
Consider two (4 core and 8 GB) virtual machines(vm_1 and vm_2) are created out of one physical physical machine (8 core 16 GB). Does it mean if I need to transfer one core from vm_1(3 core) to vm_2(4 core) , can I do that ?
Second statement it says
Thus, a physical machine and a virtual machine, both having the same hardware and software resources and capabilities, cannot perform on the same level VMs are much easier to maintain than physical servers.
Does it mean physical server(8 core 16 GB) is better in performance than virtual machine (8 core 16 GB) ?
Last thing it says
In case of server failure, it could take several days to restore a physical server to its original state. For VMs, the recovery process can be initiated in just a few clicks with the help of a previously-created VM backup.
If we have previous created backup for physical machine, won't it be equally easy to restore a physical machine with few clicks ?
user3198603
Posted 2019-03-07T16:07:53.737
Reputation: 429
1Do you have a question, or do you expect us to read a badly written blog post and then expect us to say, “That is a badly written blog post; ignore it.” In general VMs are easier to maintain and they are more flexible. I can created VMs on virtually any hardware and then just copy the VM to another piece of hardware and it will work. Not so with a disk image. The issue of performance is an edge issue at best. On most modern machines, the performance difference doesn’t outweigh the flexibility of VMs. – JakeGould – 2019-03-07T16:20:13.990
For future questions, please only ask one question per Question. Ask questions that can be answered concretely rather than philosophically (for instance, one might ask "What tools can we use to backup and restore a physical machine with few clicks and keystrokes?"). The answer to the first question regarding "moving cores" shows that you need to give it a try and test it yourself rather than asking questions. VMWare vSphere allows you to add CPU cores while the VM is on. Other virtualization solutions can do it too. – Christopher Hostage – 2019-03-07T16:45:21.143
@JakeGould you said I can created VMs on virtually any hardware and then just copy the VM to another piece of hardware and it will work. Not so with a disk image What makes it easier to copy the VM image than physical image(if hardware of machine where image needs to be copied is same) ? – user3198603 – 2019-03-07T17:16:30.917
“Not so with a disk image.” I utterly have no idea why this is an issue. A VM is a disk image. Export from one setup and import into another. Without that basic functionality cloud servers would not be able to exist. – JakeGould – 2019-03-07T17:18:26.920
@user3198603 - I routinely migrate an image of my machine to different hardware, both images of a virtual machine and a physical machine, I don't agree that an image of a physical machine cannot be migrated to another physical machine. – Ramhound – 2019-03-07T18:00:35.590
@Ramhound But the difference between a physical machine image versus a VM is with a VM you have assurance that the VM will run on another machine without any worries about drivers and such. Not always the case with a physical disk image. – JakeGould – 2019-03-07T18:39:49.447
@JakeGould - I have never personally had a problem taking of an image of one machine and restoring it to another but I use (paid) tools that make that process painless. – Ramhound – 2019-03-07T18:42:59.363
1@JakeGould What you saying is
there is assurance that image of VM will work on other VM but it's not the case with disk image.That's what I am trying to ask even image of VM must also be disk image internally . Is n't it ? Probably only difference is that in VM . you can be assured that all hardware and software will be exactly same while in case of disk image it needs to be ensured. Is that correct ? – user3198603 – 2019-03-08T02:10:59.237@user3198603 Exactly. – JakeGould – 2019-03-08T02:21:18.283