1 00:00:00,000 --> 00:00:14,240 Hey guys and welcome back. 2 00:00:14,240 --> 00:00:20,039 So in the previous nugget we saw some basic LVM configuration and we could see some of 3 00:00:20,039 --> 00:00:25,519 the tools that we could use or the commands should I say that we could use to set up this 4 00:00:25,519 --> 00:00:26,519 technology. 5 00:00:26,519 --> 00:00:32,200 Now there are some additional commands that we do want to be aware of for the purposes 6 00:00:32,200 --> 00:00:33,200 of the examination. 7 00:00:33,200 --> 00:00:37,879 Let me just tell you what some of those are and what they can actually do for us. 8 00:00:37,879 --> 00:00:43,679 Now the first one I want to talk to you about is one called PVChange and again I would encourage 9 00:00:43,679 --> 00:00:47,840 you to read the man pages on these particular commands and explore everything that they 10 00:00:47,840 --> 00:00:48,840 are capable of. 11 00:00:48,840 --> 00:00:53,879 But as a high level overview to understand what these commands do for the examination, 12 00:00:53,880 --> 00:00:59,800 what this one does, it allows us to change attributes of a physical volume. 13 00:00:59,800 --> 00:01:04,159 The next command is one called PVMove. 14 00:01:04,159 --> 00:01:08,240 What this command is going to allow us to do, it's going to allow us to move, hence 15 00:01:08,240 --> 00:01:14,640 the name, data from one physical volume to another physical volume. 16 00:01:14,640 --> 00:01:21,000 So realistically when you want to happen to downsize a volume group, i.e. remove a physical 17 00:01:21,000 --> 00:01:27,000 volume, you may want to move that data first, in which case the PVMove command is going 18 00:01:27,000 --> 00:01:29,040 to allow you to do such a thing. 19 00:01:29,040 --> 00:01:34,640 Now following on in that vein, if we have our volume group, remember that big logical 20 00:01:34,640 --> 00:01:41,280 chunk, if we want to remove one of the physical volumes from that volume group, the command 21 00:01:41,280 --> 00:01:45,079 we would use is PVRemove. 22 00:01:45,079 --> 00:01:51,519 Similarly if we want to make changes to particular attributes of a logical volume, the command 23 00:01:51,519 --> 00:01:54,719 we could use would be LVChange. 24 00:01:54,719 --> 00:02:00,359 As we can see here we're following a similar format, PVChange changes attributes of a physical 25 00:02:00,359 --> 00:02:05,560 volume, LVChange changes attributes of a logical volume. 26 00:02:05,560 --> 00:02:13,039 Now if we want to actually extend a logical volume, we could use the command LVExtend. 27 00:02:13,159 --> 00:02:18,560 Similarly if we wanted to reduce the size of a logical volume, we could use the command 28 00:02:18,560 --> 00:02:20,560 LVReduce. 29 00:02:20,560 --> 00:02:26,599 And again if we want to make changes to a volume group, the command would be VGChange. 30 00:02:26,599 --> 00:02:32,799 And if we wanted to extend the size of a volume group, make our big logical chunk even bigger, 31 00:02:32,799 --> 00:02:36,479 we would use the command VGExtend. 32 00:02:36,479 --> 00:02:41,159 Now there is not enough time, definitely not, to display all of these commands and show 33 00:02:41,280 --> 00:02:42,719 you how to work with them. 34 00:02:42,719 --> 00:02:46,000 That would mean this scale would run on for way too long. 35 00:02:46,000 --> 00:02:50,879 So as always as homework I would suggest that you use the man page on these commands, check 36 00:02:50,879 --> 00:02:51,879 them out. 37 00:02:51,879 --> 00:02:55,840 But if you want to have a full listing of the available commands that we can use, if 38 00:02:55,840 --> 00:03:02,599 I just happen to say LVM and I press help and hit enter, we can actually see all of 39 00:03:02,599 --> 00:03:03,960 the different options right here. 40 00:03:03,960 --> 00:03:09,199 So if I scroll on up, we can see here LVCreate creates a logical volume. 41 00:03:09,239 --> 00:03:14,519 LVExtends ultimately extends and adds space to your logical volume. 42 00:03:14,519 --> 00:03:23,359 We can see LVRemove, LVRename, same with PVCreate, PVMove, VGCreate, VGReduce, so on and so forth. 43 00:03:23,359 --> 00:03:28,679 So what I will do is I will give you an example of one of these commands and what we will 44 00:03:28,679 --> 00:03:32,799 do is we will extend one of our logical volumes. 45 00:03:32,799 --> 00:03:35,239 So if I hit exit and I clear the screen. 46 00:03:35,240 --> 00:03:40,800 Okay, so if I do LVDisplay to see my logical volume and of course I'm always forgetting 47 00:03:40,800 --> 00:03:45,280 and my sudo command, so LVDisplay with sudo, hit enter. 48 00:03:45,280 --> 00:03:52,280 So how about we extend medium chunk and we will give it an additional let's say 100meg. 49 00:03:52,280 --> 00:03:57,560 Now we can see here the actual path here which we saw before but I do actually feel like I 50 00:03:57,560 --> 00:04:00,760 should make a note here just for clarity. 51 00:04:00,759 --> 00:04:08,639 See this path format of dev followed by the volume group followed by the logical volume. 52 00:04:08,639 --> 00:04:15,639 This is actually the naming convention with respect to LVM1 and you actually still see 53 00:04:15,639 --> 00:04:19,319 this even when using LVM2 which we have installed. 54 00:04:19,319 --> 00:04:22,519 I believe this is for backwards compatibility reasons. 55 00:04:22,519 --> 00:04:28,920 However you will have noticed in the previous nuggets we also saw the format of dev forward slash 56 00:04:28,920 --> 00:04:35,120 mapper forward slash and then the last part was the volume group with a hyphen and then 57 00:04:35,120 --> 00:04:37,000 the logical volume. 58 00:04:37,000 --> 00:04:42,080 This naming convention is actually the newer naming convention for LVM2. 59 00:04:42,080 --> 00:04:48,120 So both of these are kind of accepted albeit this one is the more modern and up to date 60 00:04:48,120 --> 00:04:49,120 one. 61 00:04:49,120 --> 00:04:54,960 So the command I will do is I will say sudo LV extend and I'll do dash L and now what 62 00:04:54,959 --> 00:04:59,120 I want to do is to specify the new size I want this to be. 63 00:04:59,120 --> 00:05:02,399 So I want to increase it by 100 to 600. 64 00:05:02,399 --> 00:05:05,239 I'm not going to say add 100. 65 00:05:05,239 --> 00:05:08,959 I'm actually going to give the new fixed size of 600. 66 00:05:08,959 --> 00:05:15,439 And I'll now say dev my storage chunk and then the name medium chunk. 67 00:05:15,439 --> 00:05:21,479 If I hit enter we can see here we have now successfully resized the medium chunk logical 68 00:05:21,480 --> 00:05:24,439 volume to be 600 megs. 69 00:05:24,439 --> 00:05:31,280 If I do my sudo LV display we can now see this has actually been resized. 70 00:05:31,280 --> 00:05:35,759 Now one thing I want to note is that if we want to do this again let me extend it maybe 71 00:05:35,759 --> 00:05:37,259 to 700. 72 00:05:37,259 --> 00:05:41,439 I will actually use the newer naming convention. 73 00:05:41,439 --> 00:05:46,439 So what I will do here is I will say sudo LV extend and I'll say dash L and I'll now 74 00:05:46,439 --> 00:05:49,160 make this 700 meg. 75 00:05:49,320 --> 00:05:54,240 This time I'll use a convention of dev forward slash mapper and now I'm going to say the 76 00:05:54,240 --> 00:05:58,320 volume group hyphen the logical volume. 77 00:05:58,320 --> 00:06:04,920 So if I hit enter now notice this also works and again if we display our outputs we can 78 00:06:04,920 --> 00:06:09,120 see here this has now been displayed to 700 meg. 79 00:06:09,120 --> 00:06:13,200 Now the last thing I just want to briefly cover is remember we talked about the ability 80 00:06:13,199 --> 00:06:19,479 of LVM to be able to create snapshots so that we have a perfect frozen image from a 81 00:06:19,479 --> 00:06:23,719 particular time that we can then use to revert back to. 82 00:06:23,719 --> 00:06:25,719 Let me show you how we can actually do this. 83 00:06:25,719 --> 00:06:32,039 If I say sudo LV display and I scroll on up we can see we have this LV right here. 84 00:06:32,039 --> 00:06:37,759 What if I want to be able to create a snapshot of this logical volume in its current state 85 00:06:37,759 --> 00:06:41,919 so that I could reverse back and go to this save state. 86 00:06:41,920 --> 00:06:47,120 In the event of maybe a disaster say for example so what we're going to do is we're going to 87 00:06:47,120 --> 00:06:52,720 take a note of the path here or alternatively we could use the dev mapper myStoriesChunk 88 00:06:52,720 --> 00:06:57,480 hyphen littleChunk naming convention if we so choose but for now I'll just keep it simple 89 00:06:57,480 --> 00:07:01,759 and copy this path and I'll show you the syntax we need to use. 90 00:07:01,759 --> 00:07:07,720 The way we can do this is again by using the LV create command I will say dash L the size 91 00:07:07,720 --> 00:07:14,680 is going to be 52 meg and to create this snapshot we're going to have to use the dash s flag 92 00:07:14,680 --> 00:07:20,480 this ultimately will generate the snapshot and now I'm going to say dash n to give this 93 00:07:20,480 --> 00:07:26,960 snapshot a name so I'll just call this something identifiable so I'll say littleChunk snap1 94 00:07:26,960 --> 00:07:31,800 which is the very first snapshot that I'm going to take of this logical volume and now I'm 95 00:07:31,840 --> 00:07:39,920 going to specify the path so I'll say dev myStorageChunk and then littleChunk so if I hit enter now 96 00:07:39,920 --> 00:07:46,160 we can see here that this logical volume has actually been generated so as we can see here 97 00:07:46,160 --> 00:07:52,720 with LVM we do have many commands to perform many different tasks LVM is very very comprehensive 98 00:07:52,720 --> 00:07:58,040 you can do so much with it that is why I would always encourage you to take this further explore 99 00:07:58,120 --> 00:08:03,160 those commands we talked about read demand pages and do a little labbing until you feel 100 00:08:03,160 --> 00:08:08,600 confident and familiar with the technology but ultimately those are the core concepts you 101 00:08:08,600 --> 00:08:13,720 want to understand for the purposes of the Lpik2 examination with respect to LVM so I hope this 102 00:08:13,720 --> 00:08:16,439 has been informative for you and I'd like to thank you for viewing.