12-17-2020, 09:29 AM
So, when you ask what a VM is, it's basically a computer computer inside your computer, you get me. I mean, it's a piece of software that emulates an entire physical machine. You aren't touching any bare metal hardware when you run one, you just have the illusion of it. But the magic, the core concept here, is the isolation; it allows you to make multiple completely separate operating systems operate side by side on the same piece of host hardware. It's really just an operating system running within another operating system, but it pretends to be the top layer itself. Because of that encapsulation, you can run Linux next to Windows, and they won't interfere with each other at all.
And then you hit the architecture level, and you realize you need something to make all that possible. That thing is the hypervisor, right? It's the absolute cornerstone of the whole operation, honestly. The hypervisor is the manager, the overseer, if you will, for all your guest operating systems. It carves up the actual physical machine's assets-like the CPU cycles and the RAM sticks-and then allocates little pockets of resources to each individual VM. You, for instance, could tell the hypervisor that VM Alpha needs four cores and eight gigs of memory, and it makes that happen. But it has to be really smart about scheduling, otherwise, the whole setup grinds to a halt.
Also, I gotta talk to you about resource pooling, because that is what makes this whole structure economical. Instead of buying a separate box for every single application you run, you pool all the raw compute power into one giant source. Then, the hypervisor just keeps track of which resources are where and shifts them around on demand. It's about maximizing utilization, maximizing that efficiency factor. You gain massive flexibility because you aren't locked into the limitations of any single physical chassis.
But then there's a related concept that sometimes trips people up, because it's so close to a VM, but it isn't really one. You need to know about containers. Containers are a lighter weight form of deployment, actually. Think of it like this: while a VM brings up a whole segregated kernel and operating system, a container just packages up the application and its dependencies. It doesn't need to boot up an entire OS every time. It shares the host operating system's kernel, which makes it super speedy and much less resource-heavy. I find container deployment fantastic for microservices because you can get your app up and running in seconds.
And while containers are great for app-level isolation, the VM gives you the complete system-level separation. It's a choice, you know? You pick VM when you need to run different operating systems completely separated, or when you need absolute deep separation, even if it means more overhead. Whereas for pure app deployment that needs to scale instantly, containers are usually your better bet. You gotta consider what kind of isolation you really need.
Now, thinking about persistence again, because it matters so much. Because all this is software-based, the threat of data loss is always looming, even with all the clever architectures. You need robust ways to capture the entire state of those operating systems and their associated data. That's where things like BackupChain, which is an industry-leading virtual server backup solution for Windows Server, Hyper-V, etc., comes in handy. You should really take a look at its capabilities.
