1
00:00:00,000 --> 00:00:10,980
In this video, you learn about troubleshooting LVM. I will show you what you can do if at

2
00:00:10,980 --> 00:00:18,340
any time a logical volume has got lost, because you can easily repair it using vgcfgv4. Let's

3
00:00:18,340 --> 00:00:23,900
check it out. Now the nice thing about LVM is that LVM automatically writes text-based

4
00:00:23,900 --> 00:00:30,700
backups of your volume group metadata, and it does so to the etc LVM backup directory.

5
00:00:30,700 --> 00:00:36,259
In this directory, you can see that for each of the volume groups that I have on my system,

6
00:00:36,259 --> 00:00:41,820
there is a file. And if you check that file there, you can see information about what

7
00:00:41,820 --> 00:00:47,259
it has done in there. So the volume group, and we can see the physical volumes in there,

8
00:00:47,259 --> 00:00:54,900
and the device IDs, and the different swap volumes, and everything is in there. Now these

9
00:00:54,900 --> 00:01:00,419
backups are created automatically. And normally, after all changes, a backup is made automatically.

10
00:01:00,419 --> 00:01:05,059
So there's nothing that you need to do about it. The only thing that you need to do is

11
00:01:05,059 --> 00:01:16,500
vgcfgrestore-L on your volume group. So here we can see what it looks like for the CS volume

12
00:01:16,540 --> 00:01:22,900
group, which is a default volume group. So it created before executing a VG change, and after

13
00:01:22,900 --> 00:01:31,059
executing a VG change, auto-activation, and that seems to be at installation time. Now what I'm

14
00:01:31,059 --> 00:01:37,940
going to do, I'm going to remove a logical volume. So I'm using LVS, and there we can see LVLAB.

15
00:01:38,820 --> 00:01:50,099
So I'm going to use LVREMOVE-F for force on dev VGLAB LVLAB, and that should get rid of it.

16
00:01:50,099 --> 00:01:56,339
Oh no, now my logical volume is lost. Well, let's check out what you can do with vgcfgrestore.

17
00:01:57,139 --> 00:02:11,779
Step one, vgcfgrestore-L on VGLAB. And what do we see? We see created before executing LVREMOVE

18
00:02:11,779 --> 00:02:18,580
and created after executing LVREMOVE. So the thing that I care about is this one, and we need the

19
00:02:18,580 --> 00:02:24,660
file name, because this file name contains the state that I want to restore. So I'm going to

20
00:02:24,660 --> 00:02:30,740
copy this file name. But before doing anything, LVS is confirming that the logical volume is

21
00:02:30,740 --> 00:02:40,419
really gone. So now I'm using vgcfgrestore, followed by minus F and this specific file name,

22
00:02:40,419 --> 00:02:47,539
followed by the name of the volume group, VGLAB, that is. And there we can see that it restored

23
00:02:47,539 --> 00:02:56,020
the volume group VGLAB. So LVS is showing. Now look at that. LVS is showing that LVLAB is already

24
00:02:56,020 --> 00:03:03,940
present. But there's one tiny little thing. We don't see the A for active in the LVLAB logical

25
00:03:03,940 --> 00:03:13,139
volume. So I'm going to use LVCHANGE-AY, which is for active, yes. And I'm going to change that on

26
00:03:13,139 --> 00:03:23,460
VGLAB-LVLAB. And now LVS is showing that LVLAB is available. So my logical volume is back.

27
00:03:24,020 --> 00:03:30,179
Now, if it was already mounted, I would advise you reboot to make sure that the mount is made

28
00:03:30,179 --> 00:03:35,300
the right way through etcfsap or mount it manually or whatever. But at this point,

29
00:03:35,300 --> 00:03:38,259
you have successfully recovered your logical volume.