WEBVTT 00:00:00.000 --> 00:00:02.300 Welcome back to vSphere 8 in the real world. 00:00:02.300 --> 00:00:04.100 And now we're going to discuss snapshots. 00:00:04.100 --> 00:00:09.300 So a snapshot is not really a copy of a VMDK. 00:00:09.300 --> 00:00:14.000 What a snapshot is, it's a delta of a VMDK. 00:00:14.000 --> 00:00:17.660 So let's say we have a virtual disk, right? 00:00:17.660 --> 00:00:20.860 And so in VMware, our virtual disks are VMDK files. 00:00:20.860 --> 00:00:23.360 And if our VM is called demo one, 00:00:23.360 --> 00:00:27.299 then we have a file for the hard disk. 00:00:27.299 --> 00:00:32.599 By default, that file would be called demo1.vmdk. 00:00:32.599 --> 00:00:35.400 And that is the virtual disk, that first virtual disk 00:00:35.400 --> 00:00:38.099 for this particular virtual machine. 00:00:38.099 --> 00:00:41.200 And when I write a file to that virtual machine, 00:00:41.200 --> 00:00:43.000 it gets written to that VMDK. 00:00:43.000 --> 00:00:45.200 If I delete a file off the virtual disk, 00:00:45.200 --> 00:00:47.700 it gets removed from within that VMDK. 00:00:47.700 --> 00:00:51.000 But it's all written within that one file. 00:00:51.000 --> 00:00:55.200 What can happen is I can decide I want to take a snapshot. 00:00:55.200 --> 00:00:57.700 And when I take a snapshot, what happens 00:00:57.700 --> 00:01:02.099 is that VMDK file now becomes a read-only file. 00:01:02.099 --> 00:01:05.900 I'm not going to write any more changes to that. 00:01:05.900 --> 00:01:09.000 A new file is going to get created. 00:01:09.000 --> 00:01:11.300 That's going to be my delta file. 00:01:11.300 --> 00:01:14.099 So I'll have my demo1.vmdk. 00:01:14.099 --> 00:01:18.699 And I'll have another file called delta1-0000, 00:01:18.699 --> 00:01:21.800 for exactly the number of zeros, 1.vmdk. 00:01:21.800 --> 00:01:27.099 And that series of zeros, 1.vmdk, that's my delta file. 00:01:27.099 --> 00:01:28.900 That's my first delta file. 00:01:28.900 --> 00:01:32.500 So I have my primary file that is now my read-only file. 00:01:32.500 --> 00:01:35.199 And then I have that delta file. 00:01:35.199 --> 00:01:38.400 Now what happens, when I want to read something 00:01:38.400 --> 00:01:40.599 from that virtual disk, it reads it 00:01:40.599 --> 00:01:44.699 from that original file, that read-only VMDK file. 00:01:44.699 --> 00:01:47.300 But if I open up a Word document from there, 00:01:47.300 --> 00:01:49.199 I just read it out of that read-only file. 00:01:49.199 --> 00:01:50.699 I open it in Word. 00:01:50.699 --> 00:01:52.199 I start making changes to it. 00:01:52.199 --> 00:01:55.199 I click on Save to save my changes. 00:01:55.199 --> 00:01:58.599 Those changes don't get written to that read-only file. 00:01:58.599 --> 00:02:01.300 They now get written to that delta file. 00:02:01.300 --> 00:02:04.300 So in the operating system, the guest operating system says, 00:02:04.300 --> 00:02:08.699 oh, I want these certain blocks that have that Word document. 00:02:08.699 --> 00:02:11.899 The hypervisor knows, oh, those blocks that are pointed here 00:02:11.899 --> 00:02:15.600 are actually now in this other file down over here. 00:02:15.600 --> 00:02:19.899 And as I open files and make changes to the files 00:02:19.899 --> 00:02:23.199 and save those files, they get written to that delta file. 00:02:23.199 --> 00:02:25.199 And that delta file starts to grow. 00:02:25.199 --> 00:02:31.600 So what can happen is maybe my original disk was 100 gigs. 00:02:31.600 --> 00:02:35.100 And of that 100 gigs, 50 gigs of it 00:02:35.100 --> 00:02:39.300 is documents and files and pictures and things like that. 00:02:39.300 --> 00:02:43.600 Over time, if I never deleted that snapshot 00:02:43.600 --> 00:02:46.300 and I touched every single file that 00:02:46.300 --> 00:02:51.100 was on that virtual disk, all of a sudden, 00:02:51.100 --> 00:02:54.100 this disk is 100 gigs, which is maybe 00:02:54.100 --> 00:02:58.199 the max size for that virtual disk, or close to. 00:02:58.199 --> 00:03:00.300 And my delta file is now 50 gigs, 00:03:00.300 --> 00:03:04.300 because that 50 gigs of files up here 00:03:04.300 --> 00:03:07.800 all got changed and written to that delta file. 00:03:07.800 --> 00:03:10.600 And then over some time, OK, I'm writing changes 00:03:10.600 --> 00:03:11.500 and I'm doing things. 00:03:11.500 --> 00:03:12.500 Everything's going fine. 00:03:12.500 --> 00:03:14.300 I take another snapshot. 00:03:14.300 --> 00:03:22.100 Now I get a demo1-00002.vmdk. 00:03:22.100 --> 00:03:25.699 And when I say I want to read operating system 00:03:25.699 --> 00:03:29.199 files that haven't changed this entire time, 00:03:29.199 --> 00:03:32.699 I'm getting those from that first original vmdk file, 00:03:32.699 --> 00:03:35.000 demo1.vmdk, and I'm reading those 00:03:35.000 --> 00:03:36.800 and I'm running the operating system. 00:03:36.800 --> 00:03:39.800 But when I want that Word document that I changed, 00:03:39.800 --> 00:03:43.699 that goes to that first snapshot file, 00:03:43.699 --> 00:03:47.399 the 00001.vmdk, which is now read-only. 00:03:47.399 --> 00:03:48.899 All I can do is read from it now. 00:03:48.899 --> 00:03:52.399 If I create another snapshot, I read the file from there. 00:03:52.399 --> 00:03:55.199 I go in, I make changes, I click on Save, 00:03:55.199 --> 00:03:59.199 and the changes get written to my second delta 00:03:59.199 --> 00:04:02.399 file, my 0002.vmdk. 00:04:02.399 --> 00:04:04.100 Now I've got two snapshots. 00:04:04.100 --> 00:04:07.800 One is read-only and two is the one I can write to. 00:04:07.800 --> 00:04:11.300 And maybe that grows, and I change 10 gigs of data 00:04:11.300 --> 00:04:14.500 over this time, and it gets written to that second file. 00:04:14.500 --> 00:04:17.000 Then I create a third snapshot. 00:04:17.000 --> 00:04:18.799 And you can kind of see what's happening now. 00:04:18.799 --> 00:04:20.899 My original VM that was 100 gigs, 00:04:20.899 --> 00:04:23.100 and I've got 100 gigs of data, is now 00:04:23.100 --> 00:04:28.299 taking up 150 gigs, 170 gigs, 200 gigs. 00:04:28.299 --> 00:04:30.500 And I create more snapshots, those snapshot files 00:04:30.500 --> 00:04:32.299 start to grow, and I create more snapshots, 00:04:32.299 --> 00:04:33.799 those snapshot files start to grow. 00:04:33.799 --> 00:04:38.100 All of a sudden, this little simple 100-gig virtual machine 00:04:38.100 --> 00:04:42.299 is taking up 1,000 gigabytes of space on my storage array. 00:04:42.299 --> 00:04:46.100 So I keep taking snapshots and not deleting them. 00:04:46.100 --> 00:04:50.200 So one, I'm not using my storage very efficiently. 00:04:50.200 --> 00:04:53.500 Secondly, what happens is it will say, 00:04:53.500 --> 00:04:55.500 oh, you want this file here. 00:04:55.500 --> 00:04:59.500 Oh, but actually, it's pointing to the snapshot one. 00:04:59.500 --> 00:05:01.299 Snapshot one points to snapshot two. 00:05:01.299 --> 00:05:02.899 Snapshot two points to snapshot three. 00:05:03.000 --> 00:05:05.000 Snapshot three points to that snapshot four. 00:05:05.000 --> 00:05:07.700 Oh, here it is on four, or here it is on five. 00:05:07.700 --> 00:05:09.200 That all took time. 00:05:09.200 --> 00:05:12.600 And so now, my performance is really starting to lag. 00:05:12.600 --> 00:05:15.399 I'm not using my space efficiently. 00:05:15.399 --> 00:05:17.299 My performance is lagging. 00:05:17.299 --> 00:05:19.700 And it's not unusual. 00:05:19.700 --> 00:05:24.299 For some reason, in the middle of that, my snapshot three 00:05:24.299 --> 00:05:27.700 is supposed to point to snapshot four, and that pointer breaks. 00:05:27.700 --> 00:05:30.600 And all of a sudden, now my snapshot chain is broken. 00:05:30.600 --> 00:05:33.700 And everything below that snapshot chain is lost. 00:05:33.700 --> 00:05:36.399 And my VM won't even start up anymore, 00:05:36.399 --> 00:05:39.600 seeing that happen more than once. 00:05:39.600 --> 00:05:40.700 You can go in there. 00:05:40.700 --> 00:05:41.600 It can be fixed. 00:05:41.600 --> 00:05:44.000 You can manually edit and try and fix that. 00:05:44.000 --> 00:05:46.399 I've heard of, never used one myself, third-party tools 00:05:46.399 --> 00:05:48.799 that you can use to try and find all your snapshot chains 00:05:48.799 --> 00:05:50.399 and fix them for you. 00:05:50.399 --> 00:05:52.000 A lot of times, it's kind of a manual 00:05:52.000 --> 00:05:54.100 go-in-there-and-fixing kind of process. 00:05:54.100 --> 00:05:57.500 So creating snapshots, and snapshot 00:05:57.500 --> 00:06:00.899 after snapshot after snapshot, and not deleting them 00:06:00.899 --> 00:06:03.500 is a really bad practice. 00:06:03.500 --> 00:06:07.000 I recommend that if we're taking snapshots, 00:06:07.000 --> 00:06:08.500 and one of the more common reasons 00:06:08.500 --> 00:06:11.000 why is we're installing updates. 00:06:11.000 --> 00:06:12.799 I'm updating the operating system. 00:06:12.799 --> 00:06:14.899 I'm updating an application. 00:06:14.899 --> 00:06:18.700 Maybe I'm making the change to some data in an application. 00:06:18.700 --> 00:06:21.100 And I'm like, OK, this is like maintenance type of changes 00:06:21.100 --> 00:06:22.700 to my data. 00:06:22.700 --> 00:06:24.200 I've taken the database offline. 00:06:24.200 --> 00:06:25.500 I'm going to do some maintenance, 00:06:25.500 --> 00:06:27.200 make some changes. 00:06:27.200 --> 00:06:29.799 But I'm worried that I might end up screwing this up. 00:06:29.799 --> 00:06:31.100 I'm going to take a snapshot. 00:06:31.100 --> 00:06:32.399 Go in there and make my changes. 00:06:32.399 --> 00:06:32.899 Test. 00:06:32.899 --> 00:06:33.799 Everything's good. 00:06:33.799 --> 00:06:35.100 Delete my snapshot. 00:06:35.100 --> 00:06:35.700 Test. 00:06:35.700 --> 00:06:36.600 It's bad. 00:06:36.600 --> 00:06:39.399 Roll back my snapshot and delete that snapshot. 00:06:39.399 --> 00:06:41.799 Roll back to what I had and delete the snapshot. 00:06:41.799 --> 00:06:45.200 So you have a way of recovering. 00:06:45.200 --> 00:06:48.100 What snapshots, though, are not, and they 00:06:48.100 --> 00:06:52.100 get confused for this often, they're not a backup. 00:06:52.100 --> 00:06:53.899 Because as an example, I just mentioned, 00:06:53.899 --> 00:06:56.399 if that snapshot chain were to break, 00:06:56.500 --> 00:06:58.700 I could have lost that VM and all the data 00:06:58.700 --> 00:06:59.700 that would be on that VM. 00:06:59.700 --> 00:07:00.899 It won't start up now. 00:07:00.899 --> 00:07:03.399 So how do I recover from that? 00:07:03.399 --> 00:07:05.200 Well, maybe you can fix the chain. 00:07:05.200 --> 00:07:09.500 Or you can go to your backups and restore that VM 00:07:09.500 --> 00:07:12.000 and get it back up and running. 00:07:12.000 --> 00:07:13.700 Snapshots are not a backup. 00:07:13.700 --> 00:07:16.100 If there's a corruption somewhere 00:07:16.100 --> 00:07:20.700 in that virtual machine chain, the snapshot 00:07:20.700 --> 00:07:22.500 does not fix it for you. 00:07:22.500 --> 00:07:24.399 You can roll back and lose data maybe. 00:07:24.399 --> 00:07:27.500 Maybe the break is somewhere low in the chain. 00:07:27.500 --> 00:07:29.500 And you can roll to up earlier before it 00:07:29.500 --> 00:07:32.500 and just lose everything below that. 00:07:32.500 --> 00:07:34.100 That's not a backup. 00:07:34.100 --> 00:07:37.399 So snapshots are not backups. 00:07:37.399 --> 00:07:39.500 They're just a place and time holder 00:07:39.500 --> 00:07:41.500 that you can roll back to. 00:07:41.500 --> 00:07:45.200 So they are kind of a safety measure against changes 00:07:45.200 --> 00:07:47.899 you didn't really want or changes that messed things up, 00:07:47.899 --> 00:07:49.899 an update that screwed things up. 00:07:49.899 --> 00:07:52.600 But they're not a replace for a backup. 00:07:52.700 --> 00:07:56.399 Whereas if you had a true backup and that storage got corrupted, 00:07:56.399 --> 00:07:57.899 that virtual disk got corrupted, you 00:07:57.899 --> 00:08:01.299 have an entire copy of that VM someplace else 00:08:01.299 --> 00:08:04.299 on different storage that's not corrupted 00:08:04.299 --> 00:08:06.399 that you can restore that VM from. 00:08:06.399 --> 00:08:09.000 So snapshots and backups are not the same thing. 00:08:09.000 --> 00:08:10.500 They get often confused for being 00:08:10.500 --> 00:08:12.200 similar to the same thing. 00:08:12.200 --> 00:08:14.000 They're not the same thing at all. 00:08:14.000 --> 00:08:16.600 One is just a place and time holder 00:08:16.600 --> 00:08:19.299 for a certain configuration. 00:08:19.299 --> 00:08:23.100 The other one is an actual protected copy 00:08:23.100 --> 00:08:26.700 of your virtual machine, the operating system, your data, 00:08:26.700 --> 00:08:29.299 your applications, all those kinds of things. 00:08:29.299 --> 00:08:30.299 That's a backup. 00:08:30.299 --> 00:08:32.299 So don't confuse snapshots for backups. 00:08:32.299 --> 00:08:36.500 So snapshots are fantastic for I'm going to run some updates. 00:08:36.500 --> 00:08:40.000 And before I update Windows, we take snapshots. 00:08:40.000 --> 00:08:41.299 That's fantastic. 00:08:41.299 --> 00:08:43.900 OK? 00:08:43.900 --> 00:08:45.700 So to take a snapshot is pretty easy. 00:08:45.700 --> 00:08:47.799 You just go to the VM that you want to snapshot. 00:08:47.799 --> 00:08:49.599 You're going to right click on that one. 00:08:49.599 --> 00:08:50.500 Go to your snapshots. 00:08:50.500 --> 00:08:52.299 And you can just say take snapshot. 00:08:52.299 --> 00:08:54.900 And when in there, you can go in there and give it a name. 00:08:54.900 --> 00:08:57.200 It's really a great idea not to use 00:08:57.200 --> 00:08:59.000 the default name, which is basically 00:08:59.000 --> 00:09:02.200 like the virtual machine name and update and timestamp. 00:09:02.200 --> 00:09:04.500 Something descriptive, especially 00:09:04.500 --> 00:09:06.799 in the description, a longer description, 00:09:06.799 --> 00:09:09.000 but even in the name, you might say 00:09:09.000 --> 00:09:11.900 before installing Windows Update and the date and time, right? 00:09:11.900 --> 00:09:15.200 Or before installing new antivirus and a date and time. 00:09:15.200 --> 00:09:20.099 You might put some detail about why you're taking a snapshot. 00:09:20.099 --> 00:09:21.299 This is before this. 00:09:21.299 --> 00:09:23.900 This is after that. 00:09:23.900 --> 00:09:25.299 Things like that. 00:09:25.299 --> 00:09:28.500 Snapshots are super helpful for that kind of thing. 00:09:28.500 --> 00:09:31.000 So maybe we're going to go in and say 00:09:31.000 --> 00:09:33.299 before installing new antivirus. 00:09:33.299 --> 00:09:35.099 Well, if you're installing a new antivirus, 00:09:35.099 --> 00:09:37.500 you probably uninstalled your old one, right? 00:09:37.500 --> 00:09:41.700 So take a snapshot before installing old antivirus. 00:09:41.700 --> 00:09:44.700 Then after, take another one, after uninstalling 00:09:44.799 --> 00:09:46.099 your old antivirus. 00:09:46.099 --> 00:09:49.700 Then before installing the new one is your after, 00:09:49.700 --> 00:09:51.700 after installing new antivirus. 00:09:51.700 --> 00:09:57.700 Then take another one, updated the virus definitions 00:09:57.700 --> 00:10:00.200 or updated the version or something like that, 00:10:00.200 --> 00:10:02.700 ran a complete scan with antivirus. 00:10:02.700 --> 00:10:04.900 So I'm taking a snapshot before I run a complete scan. 00:10:04.900 --> 00:10:08.500 So doing one simple task of uninstalling your old antivirus, 00:10:08.500 --> 00:10:11.099 installing the new antivirus, updating the definitions, 00:10:11.099 --> 00:10:13.799 running a complete scan of the system with the new antivirus, 00:10:13.799 --> 00:10:15.299 you might take four or five snapshots 00:10:15.299 --> 00:10:17.099 because maybe somewhere along the way, 00:10:17.099 --> 00:10:18.599 something was sideways. 00:10:18.599 --> 00:10:22.200 So I want a snapshot of my VM before I uninstalled the old. 00:10:22.200 --> 00:10:24.400 I want a snapshot after I uninstalled the old 00:10:24.400 --> 00:10:26.099 before I installed the new. 00:10:26.099 --> 00:10:27.700 And then I want a snapshot with the new 00:10:27.700 --> 00:10:28.900 before the new definitions 00:10:28.900 --> 00:10:30.700 because where did this go sideways on me? 00:10:30.700 --> 00:10:32.099 Sometimes things are going wrong. 00:10:32.099 --> 00:10:33.599 Like where did this go wrong? 00:10:33.599 --> 00:10:35.500 Let's roll back to here and see what's going on. 00:10:35.500 --> 00:10:37.000 Okay, here we're fine. 00:10:37.000 --> 00:10:38.299 Okay, let's roll back to here. 00:10:38.299 --> 00:10:39.299 Here we're fine. 00:10:39.299 --> 00:10:40.200 Oh, let's go to here. 00:10:40.200 --> 00:10:41.500 Oh, when I get to this point here, 00:10:41.500 --> 00:10:43.400 this is where things start to break, right? 00:10:43.400 --> 00:10:45.099 So you want to have a record, you know, 00:10:45.099 --> 00:10:48.799 and a way of going back to these different points in time 00:10:48.799 --> 00:10:50.099 and checking that out. 00:10:50.099 --> 00:10:53.799 So your name should be descriptive of where you are. 00:10:53.799 --> 00:10:56.799 And then the actual description can be even more descriptive, 00:10:56.799 --> 00:10:57.700 more detailed. 00:10:57.700 --> 00:10:59.200 But you want to be able to look at the name real quickly 00:10:59.200 --> 00:11:02.299 and figure out where you are. 00:11:02.299 --> 00:11:04.900 You can also go in and rather than say take a snapshot, 00:11:04.900 --> 00:11:06.200 you want to manage a snapshot. 00:11:06.200 --> 00:11:09.799 So there it will show you the original virtual disk 00:11:09.799 --> 00:11:11.500 and then each of those snapshots, 00:11:11.500 --> 00:11:14.000 those deltas will be listed below that 00:11:14.000 --> 00:11:15.099 and it'll tell you where you are. 00:11:15.099 --> 00:11:16.599 If you're down at the bottom, 00:11:16.599 --> 00:11:18.299 if you just keep taking them and taking them, 00:11:18.299 --> 00:11:20.099 you never do anything else, it'll say you're here, 00:11:20.099 --> 00:11:22.900 you're after that last snapshot. 00:11:22.900 --> 00:11:25.200 Or maybe you went and said, okay, 00:11:25.200 --> 00:11:27.500 so I, you know, have my antivirus. 00:11:27.500 --> 00:11:29.099 Here's where I uninstalled my antivirus. 00:11:29.099 --> 00:11:31.099 Here's where I installed the new antivirus. 00:11:31.099 --> 00:11:32.900 Here's where I updated my definitions. 00:11:32.900 --> 00:11:33.900 Wait, something's wrong. 00:11:33.900 --> 00:11:35.700 Without deleting these snapshots, 00:11:35.700 --> 00:11:37.099 I can click on one, 00:11:37.099 --> 00:11:40.200 maybe I go back to after I uninstalled the antivirus 00:11:40.200 --> 00:11:41.900 and before I installed the new. 00:11:41.900 --> 00:11:43.599 I can jump to that point in time, 00:11:43.599 --> 00:11:45.400 revert the machine to there. 00:11:45.400 --> 00:11:47.099 I still have those snapshots below 00:11:47.099 --> 00:11:48.799 and I can say, is everything good here? 00:11:48.799 --> 00:11:50.000 Yeah, everything's good here. 00:11:50.000 --> 00:11:52.099 All right, let's jump to the snapshot 00:11:52.099 --> 00:11:54.400 where I have the antivirus installed. 00:11:54.400 --> 00:11:56.900 Okay, so I click on that one, I say jump to here. 00:11:56.900 --> 00:11:57.599 Is everything good? 00:11:57.599 --> 00:11:58.799 Yep, everything's good here. 00:11:58.799 --> 00:12:00.400 All right, so let's look at 00:12:00.400 --> 00:12:02.200 after we updated the antivirus definitions. 00:12:02.200 --> 00:12:03.599 I go to there, everything good? 00:12:03.599 --> 00:12:04.700 Everything's good here. 00:12:04.700 --> 00:12:06.099 And you can keep stepping through there. 00:12:06.099 --> 00:12:10.700 So you can go up and down through that chain of snapshots 00:12:10.700 --> 00:12:12.700 from the manage option. 00:12:12.700 --> 00:12:14.599 And then revert means you want to revert. 00:12:14.599 --> 00:12:18.000 Consolidate means that I want to delete one 00:12:18.000 --> 00:12:19.799 and consolidate it into the one above. 00:12:19.799 --> 00:12:20.900 So I only have the one. 00:12:20.900 --> 00:12:23.900 I'm deleting one and consolidating into another one. 00:12:23.900 --> 00:12:29.099 And then delete will actually just roll it up, right? 00:12:29.099 --> 00:12:31.700 And so I can say I want to delete all the snapshots. 00:12:31.700 --> 00:12:33.700 If I go in and say I want to delete all the snapshots, 00:12:33.700 --> 00:12:35.400 it's going to take the state I'm in 00:12:35.500 --> 00:12:38.000 and roll it up into the main VMDK file. 00:12:38.000 --> 00:12:40.000 So let's go back to that example 00:12:40.000 --> 00:12:44.599 where I have my main demo1.vmdk 00:12:44.599 --> 00:12:48.200 and then I have my snapshot1, my snapshot2, my snapshot3 00:12:48.200 --> 00:12:50.000 and I'm running down below snapshot3. 00:12:50.000 --> 00:12:51.700 Everything's running fantastic. 00:12:51.700 --> 00:12:52.400 Everything's running good. 00:12:52.400 --> 00:12:54.299 I'm like, all right, I've run all my tests. 00:12:54.299 --> 00:12:55.000 I'm happy. 00:12:55.000 --> 00:12:56.500 This is where I want to be. 00:12:56.500 --> 00:12:58.599 I trust this configuration. 00:12:58.599 --> 00:12:59.799 I'm going to say delete all. 00:12:59.799 --> 00:13:02.500 What happens is it's going to write the changes 00:13:02.500 --> 00:13:05.299 that are in Delta 1 to that VMDK. 00:13:05.299 --> 00:13:07.000 And then it changes in 2 to that VMDK 00:13:07.000 --> 00:13:08.700 and then 3 to that VMDK. 00:13:08.700 --> 00:13:10.599 The more I have, the longer it's going to take 00:13:10.599 --> 00:13:12.400 to roll all that up. 00:13:12.400 --> 00:13:15.799 When I'm done, I'll end up with that 100-gig disk 00:13:15.799 --> 00:13:19.299 and just that 100-gig disk and not all the Deltas below it. 00:13:19.299 --> 00:13:21.900 But the more I have, the longer it's going to take 00:13:21.900 --> 00:13:23.599 to roll that all up. 00:13:23.599 --> 00:13:25.599 So again, having too long a chain 00:13:25.599 --> 00:13:28.700 and too big of Deltas can make deleting snapshots 00:13:28.700 --> 00:13:29.799 take a while. 00:13:29.799 --> 00:13:31.900 If you only run them for a few hours, 00:13:31.900 --> 00:13:33.099 a day or two at the most, 00:13:33.099 --> 00:13:35.299 I usually try to run them for a few hours. 00:13:35.299 --> 00:13:36.299 Depends on when I'm testing. 00:13:36.299 --> 00:13:37.400 Maybe like a Windows update, 00:13:37.400 --> 00:13:39.000 I need to run sometimes longer. 00:13:39.000 --> 00:13:42.200 I want to run for a couple of days or so. 00:13:42.200 --> 00:13:43.299 But not more than that. 00:13:43.299 --> 00:13:45.500 I try to never run a snapshot 00:13:45.500 --> 00:13:47.799 for more than a couple of days. 00:13:47.799 --> 00:13:49.700 Now that we discussed snapshots, 00:13:49.700 --> 00:13:52.500 let's go ahead and jump into our demo environment 00:13:52.500 --> 00:13:55.200 and actually create and manage some snapshots. 00:13:55.200 --> 00:13:57.200 So here we are back in our demo environment. 00:13:57.200 --> 00:13:59.400 And our demo environment is, again, 00:13:59.400 --> 00:14:01.900 being ran in VMware's hands-on lab. 00:14:01.900 --> 00:14:04.599 So it's hol.vmware.com 00:14:04.599 --> 00:14:07.000 for VMware's hands-on lab environment. 00:14:07.000 --> 00:14:09.400 And I went in and just created a clone 00:14:09.400 --> 00:14:11.099 of this Windows 10 machine. 00:14:11.099 --> 00:14:13.599 And I called it Demo01. 00:14:13.599 --> 00:14:17.799 And over here, I have the datastore 00:14:17.799 --> 00:14:19.799 that that Demo01 is in. 00:14:19.799 --> 00:14:20.900 And if we look through here, 00:14:20.900 --> 00:14:22.599 we see we have our virtual swap 00:14:22.599 --> 00:14:24.400 and some non-volatile RAM. 00:14:24.400 --> 00:14:26.700 Here's my VMDK file, right? 00:14:26.700 --> 00:14:29.700 My Demo01.vmdk, all right? 00:14:29.700 --> 00:14:31.599 And that's pretty much the only VMDK 00:14:31.599 --> 00:14:34.200 I've got on here. 00:14:34.200 --> 00:14:37.400 If I go back over here 00:14:37.400 --> 00:14:40.000 and right-click on this VM 00:14:40.000 --> 00:14:43.900 and say I want to go to snapshots, 00:14:43.900 --> 00:14:47.400 take a snapshot, and what is this? 00:14:47.400 --> 00:14:52.700 I'm going to say this is my first lab 00:14:52.700 --> 00:14:54.900 and my date and the time. 00:14:54.900 --> 00:14:56.400 I always kind of create a description, 00:14:56.400 --> 00:14:58.000 a brief description, 00:14:58.000 --> 00:14:59.700 and I note it with the date and time. 00:14:59.799 --> 00:15:04.000 So, I might say it is April 3rd in the year at 1226. 00:15:04.000 --> 00:15:06.299 And actually, the time, the hour, 00:15:06.299 --> 00:15:07.900 and the minute is actually really important 00:15:07.900 --> 00:15:10.099 because sometimes the only difference in the date 00:15:10.099 --> 00:15:12.599 and when you took it is maybe like 15 minutes later. 00:15:12.599 --> 00:15:15.299 So, the date and time is really useful. 00:15:15.299 --> 00:15:22.799 And then here I would do a detailed description 00:15:22.799 --> 00:15:28.000 of the task and the date and time. 00:15:28.000 --> 00:15:29.599 All right, so I've gone in. 00:15:29.599 --> 00:15:32.799 I get a good detailed name with the date and time. 00:15:32.799 --> 00:15:35.000 I get a good description of what I'm doing 00:15:35.000 --> 00:15:36.799 and the date and time. 00:15:36.799 --> 00:15:39.099 Include the virtual machine's memory. 00:15:39.099 --> 00:15:42.000 What this is great for 00:15:42.000 --> 00:15:45.299 is if I'm going to revert back to the snapshot later, 00:15:45.299 --> 00:15:46.400 it won't have to restart. 00:15:46.400 --> 00:15:48.799 If I don't have the memory and I revert to a snapshot, 00:15:48.799 --> 00:15:52.700 it actually has to reboot the VM with that virtual disk. 00:15:52.700 --> 00:15:54.099 If I include the RAM, 00:15:54.099 --> 00:15:57.900 I can actually jump right to this moment in time. 00:15:57.900 --> 00:16:01.099 When I click create, it's this moment in time 00:16:01.099 --> 00:16:03.099 I'm reverting back to without a reboot 00:16:03.099 --> 00:16:05.299 because I also know what the memory looked like 00:16:05.299 --> 00:16:07.400 of that VM at this moment in time. 00:16:07.400 --> 00:16:09.099 So, it's going to go in and create my snapshot. 00:16:09.099 --> 00:16:13.400 And it does, even though it's only creating a delta file, 00:16:13.400 --> 00:16:14.900 an empty delta file, 00:16:14.900 --> 00:16:18.000 and, you know, kind of migrating any write changes to it, 00:16:18.000 --> 00:16:19.000 it takes a minute to do this. 00:16:19.000 --> 00:16:20.700 So, we'll let this run for a moment 00:16:20.700 --> 00:16:23.099 and come back when it's complete. 00:16:23.099 --> 00:16:25.599 So, that snapshot is completed. 00:16:25.599 --> 00:16:27.700 So, now I'm going to go back to the folder 00:16:27.700 --> 00:16:31.900 that has this virtual machine in it. 00:16:31.900 --> 00:16:33.799 I'm going to refresh this screen. 00:16:33.799 --> 00:16:36.200 Here's my demo one. 00:16:36.200 --> 00:16:41.900 Notice that demo01-00001.vmdk. 00:16:41.900 --> 00:16:44.799 This is my snapshot file, okay? 00:16:44.799 --> 00:16:53.500 So, this is the delta file from this VMDK file, okay? 00:16:53.500 --> 00:16:58.200 This is my VMDK file, and I have my delta file. 00:16:58.200 --> 00:17:01.299 And it's about, you know, 19 megs or so. 00:17:01.299 --> 00:17:02.299 It's pretty small. 00:17:02.299 --> 00:17:05.900 As I open up that VM and start making changes, 00:17:05.900 --> 00:17:08.000 it's going to read the files 00:17:08.000 --> 00:17:12.199 that I'm wanting to change from the VMDK file. 00:17:12.199 --> 00:17:13.300 Where is my VMDK? 00:17:13.300 --> 00:17:14.300 Oh, here we go. 00:17:14.300 --> 00:17:16.300 From this VMDK file, this is going to be the source. 00:17:16.300 --> 00:17:17.800 This file is now a read-only file. 00:17:17.800 --> 00:17:19.099 It's going to read from here. 00:17:19.099 --> 00:17:20.800 And when I say save those changes, 00:17:20.800 --> 00:17:23.199 when I write changes, create a new file, 00:17:23.199 --> 00:17:25.300 write changes to old files, whatever it is, 00:17:25.300 --> 00:17:29.800 they get written to this delta file. 00:17:29.800 --> 00:17:36.199 If I go back to here, and I were, say, to go to snapshot, 00:17:36.199 --> 00:17:38.900 and I can say manage snapshots, 00:17:38.900 --> 00:17:42.800 it'll tell me, right, here's my first snapshot, 00:17:42.800 --> 00:17:44.900 and I'm here. 00:17:44.900 --> 00:17:47.599 I can still go in now, right, 00:17:47.599 --> 00:17:52.099 and say I want to take another snapshot, 00:17:52.099 --> 00:18:02.199 and I'll call this second lab snap, the date and the time, 00:18:02.199 --> 00:18:04.599 and my description. 00:18:04.599 --> 00:18:06.699 Okay, so I have a description of the second snapshot, 00:18:06.699 --> 00:18:09.699 why I'm taking it, and the date and the time, 00:18:09.699 --> 00:18:11.900 and I'm including my virtual machine memory, 00:18:11.900 --> 00:18:17.099 and say create. 00:18:17.099 --> 00:18:19.800 Again, this takes a moment to do. 00:18:19.800 --> 00:18:21.500 It's going to go in there and create that file 00:18:21.500 --> 00:18:25.599 and kind of change the original delta file, 00:18:25.599 --> 00:18:30.900 write that 001 file to a read-only file, 00:18:30.900 --> 00:18:36.400 and create me a new read-write file. 00:18:36.400 --> 00:18:40.699 So here you can see I have my first lab snapshot. 00:18:40.699 --> 00:18:43.199 Then I create that second one, and you are here. 00:18:43.199 --> 00:18:45.099 So I'm writing, everything that's, you know, 00:18:45.099 --> 00:18:47.900 getting written from this guy is being written to this file here, 00:18:47.900 --> 00:18:52.099 because I am now, at this point in time, past that snapshot. 00:18:52.099 --> 00:18:56.300 If I go to here and just refresh my screen 00:18:56.300 --> 00:19:00.900 and go to my demo 01, you'll see I now have two delta files. 00:19:00.900 --> 00:19:03.500 I have the original delta file, that 001 file, 00:19:03.500 --> 00:19:10.000 and I have the 002 file, right, the demo01-000002.bmdk. 00:19:10.099 --> 00:19:15.099 So this one here is going to be my new read-only. 00:19:15.099 --> 00:19:22.699 Again, my first source file is going to be my first VMDK file. 00:19:22.699 --> 00:19:28.199 If I can scroll and find it. There we go. 00:19:28.199 --> 00:19:30.500 So this one is where it's going to go to when I say, 00:19:30.500 --> 00:19:33.699 I want to read a file. It'll go to here to look for the file. 00:19:33.800 --> 00:19:40.000 This file might point me, say, oh, those blocks actually now are here. 00:19:40.000 --> 00:19:42.900 And if the file that I had changed from here 00:19:42.900 --> 00:19:44.800 has now been changed and written here, 00:19:44.800 --> 00:19:48.199 this one will point to this one, and then I'll get my document. 00:19:48.199 --> 00:19:51.599 And this file is going to have all the changes written to it 00:19:51.599 --> 00:19:55.199 going forward until I create a new one. 00:19:55.199 --> 00:20:01.599 I can still go back to my snapshots, and I have this guy here, 00:20:01.599 --> 00:20:04.900 but I can say, you know what, I want to go back to this guy here, 00:20:04.900 --> 00:20:10.400 and I can revert back to this point in time, right? 00:20:10.400 --> 00:20:13.900 I can say revert to there. You are here. 00:20:13.900 --> 00:20:19.199 So now this is now my new point in time I'm running from, right, 00:20:19.199 --> 00:20:24.300 to the moment when I created, or last wrote to this file. 00:20:24.300 --> 00:20:27.900 I should have left that there, there. 00:20:27.900 --> 00:20:33.400 And I'm now reading and writing from this 01 file. 00:20:33.400 --> 00:20:38.000 Okay. I can say, all right, you know what, 00:20:38.000 --> 00:20:41.099 I'm happy with this point in time that I'm at here. 00:20:41.099 --> 00:20:44.900 I want to take this, everything I have, everything I have in this file, 00:20:44.900 --> 00:20:48.599 and everything I've written since then, all of this, 00:20:48.599 --> 00:20:51.400 I want to keep all of this, and I'm going to dump everything else after that. 00:20:51.400 --> 00:20:53.300 So I'm going to say just delete all. 00:20:53.300 --> 00:20:56.800 And it'll just consult it and roll up all of this 00:20:56.800 --> 00:20:59.500 and throw out all of that. 00:20:59.500 --> 00:21:01.400 And I just got rid of all those snapshots. 00:21:01.400 --> 00:21:07.400 So now my 100-gig disk is again 100 gigs, if that's what my file is, right? 00:21:07.400 --> 00:21:09.599 If I had been writing and creating more snapshots, 00:21:09.599 --> 00:21:11.900 and my first Delta file got to 20 gigs, 00:21:11.900 --> 00:21:14.900 and my second Delta file got to be even bigger, 30 gigs, 00:21:14.900 --> 00:21:17.000 or smaller, only 10 gigs, whatever it is, 00:21:17.000 --> 00:21:22.599 so that 100-gig VM ended up becoming 130, 140 gigs. 00:21:22.599 --> 00:21:24.800 I deleted all my snapshots. 00:21:24.800 --> 00:21:27.900 Now I'm back to a 100-gig virtual machine. 00:21:27.900 --> 00:21:30.099 So that is pretty much how snapshots work.