You are watching Model three Managing virtual machines. Lesson three. Managing snapshots
by the end of this video will understand what a snapshot is,
and how to manage Snapple's
A snapshot is the preserved state off a virtual machine at a specific point in time.
A snapshot lets you create a safe environment for testing updates and patches.
And in case the system is spoiled due to those, you can quickly revert back to a priest. Natural state
snapshots are available. Both envies enter and in the host client
Essential preserves the disc state off a virtual machine by creating a new Delta disc
toe where data is written
that has a This format
with the member sign corresponds to the snapshot number,
and it preserves the original discovery in by restricting access to read. Only
a snapshot also preserves the memory state off a virgin machine. By creating this file
where again, the number sign corresponds to the snapshot member,
and it gives you the possibility to revert back to the original Veum without having the VM power off.
Now let me walk you through the process of creating snapshots,
looking to re center
and pick of Ian, for example, the Web VM
right. Click on it and choose snapshots.
Then click on. Take a snapshot
in the snapshot name. You can see that it picked up a default name toe, which it depends a time stamp.
This is a very good idea.
It helps you keep track off when this natural it was taken.
It also encourages you to write a description off this snapshot.
Why are you taking a sexual?
This is very useful to keep things tidy, especially when there are plenty of snapshots around.
You can see here that preserving the memory state of GM is enabled by default.
This allows your VM to revert back to the power state it was in when the snapshot was taken.
you can monitor these natural creation process in the recent tasks.
It could take a while, depending on the size of the content of your memory.
When it's done, it looks like nothing happened. But if you right click the VM and Goto snapshots
and then to manage naturals,
you can see here that the snapshot was created and is active because the you are here cursor is pointing to it.
Now this you are here. Cursor is very important. Actually,
it indicates which snapshot you are working under right now,
and it is your only guide, especially when you create multiple Snapple's
Let's now open E Castle to our snapshot and try and make some modifications to the disc by creating a new file.
And it's right, Hello, world
just once and then save an exit.
Let's display the content of the fire.
That's not creating new statute and make a second modification.
So let's go back to manage snapshots.
there is now a second's natural,
and we are working under it right now
because the cursor indicates it.
Let's make some modifications to the same file we created in the first snapshot.
If we display the content of file, the hello world is still there.
So the state off the previous step road was preserved.
Let's now open the file and at second line off. Hello, World
saving exit display the content
and we have made modifications to this file twice.
Let's go back to manage snapshots.
Let's not suppose that you didn't like the modifications in this snapshot, and you want to revert back to the previous natural, where there was only a single line off Hello world in the test file.
Well, to do so, we have to click on the second step salt and choose Revert to.
I know it's kind of confusing. Why don't we click directly on the first natural 10 Trees River, too?
Well, because the latest level off a snapshot always indicates that state off the parent at the moment of the snapshot. So if I revert to step foot one, I will be returning to a point in time where the first snapshot was taken, and thus it will be returning to the original P M. Actually.
Now, to make sure we reverted back to the correct state, let's display the content of our test file.
And lo and behold, we returned to a state where there was only one line off Hello world
and have you noticed something? The power state of the VM was also preserved
when we took the snapshot. Remember, we also took a snapshot of the memory state with a V M, and that's why, after we reverted back, the VM remained powered on
let's know suppose that I am happy with the modifications made to my snapshot one. And I want to keep the modifications and merge the snapshots with the original Vienna.
In this case, you need to be careful where the you are. Here cursor is if you click on delete All snap Charles and the cursor is below the latest snapshot. Then you are performing. Emerge off all your snapshots with the original Veum.
If the cursor, however, is above a snapshot and you select elite, then it will be a deletion and not emerge.
In our case, it will be emerged. So click on delete all
remember the latest state we are in. There is only one occurrence off. Hello World
anarchist file. And since this is emerged with the original Veum that had no test file in the first place, we should find the file and the hello world inside.
and lo and behold, there it is. Let's not just something else.
Let's take a snapshot.
But this time we are going to exclude the memories that wrote. This means that we are going to preserve the state off the V M disc only
and you can see that this snapshot was taken in a much shorter time.
Let's very find that the snap photos created
There is a slight difference between this snapshot and the previous worlds. If you see the little icon to the left of the snapshot name, there is no green triangle that indicates the power state of the V M.
That's because the memory was excluded from this natural.
Let's make some modifications to the text file.
Let's remove all the text,
Make sure it's all gone
now. I want to recover the state where the text was still there, so we need to revert back to when this snapshot was created
right before we deleted the hello around. So let's select the snapshot and click on reverts to
the V M powered off.
Well, it's because the memory of state was not preserved during this natural
No, let's power on the V M
Now let's verify that our test files still contains the hello world
I hope this was not too confusing for you.
Thanks for watching, and I'll see you in the next video