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In this video, I'll show you how to resize an LVM logical volume.

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Now in case you are wondering why didn't we do that in the lesson about LVM, well, simple,

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because you want to resize the file system as well.

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Let me show you what's going on.

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In this video, I want to tell you about LVM resize operations.

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So how does it work?

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Well, we are going back to the volume group.

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And when you have defined a file system, then you put it in a logical volume, and the logical

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volume is coming from the volume group.

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So let's say that on your file system, df minus h is giving you 100% full.

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And oh, no, what are you going to do?

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Well, then you are going to check in the volume group if any more storage is available.

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And if storage is available in the volume group, it's easy, it can be added to the logical

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volume.

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And the logical volume can dynamically resize including the file system.

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But sometimes you will notice that in the volume group, there is no more storage space

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available.

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Well, then it's also easy, because you are going to add in the lower layer of your LVM

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structure.

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Just add a physical volume to grow your volume group, which allows you to grow your logical

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volume.

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And that's all.

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So here, I'm going to use df minus h.

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And df minus h is showing me what?

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Oh, it's showing me that my logical volume is not mounted.

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Well, I just created it, so let me do a mount minus a and do the df minus h again.

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And there we can see on the bottom line that we have a file system slash data that is on

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the logical volume with the name devmapper vgdata lvdata.

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Now, let's imagine that this file system is running out of disk space.

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I can even do that, dd if is dev0, of is slash data slash big file.

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And that will fill up my file system pretty fast.

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So if is dev0 is using the input file dev0, the output file data big file.

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And as you can see, it fills with no space left on device.

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Oh, no.

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So du minus hs on slash data is giving me what?

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It's giving me two gigabytes in use.

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And df minus h is also showing that there is no available disk space.

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Let's click this graphical warning away because that's not something that you want to troubleshoot.

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Now, what is the issue here?

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Well, the issue here is I want more disk space to be available in my file system.

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In order to have more disk space in my file system, I need more disk space in my logical

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volume.

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In order to have more disk space in my logical volume, I need my volume group to have available

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disk space.

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And if it does not, I might have to add a new LVM storage device and add it to the volume

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group.

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So the first thing to do is check out the volume group, vgs is how I'm doing it.

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And here we can see the VG data details with V3 on VG data set to zero.

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So that is not going to work.

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So I need to start all the way at the bottom using fdisk.

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So lsblk is showing my block devices, and I'm going to use fdisk, which in my opinion

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is the most powerful partitioning utility on slash dev slash sdb.

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I'm ignoring these warnings in red because I know what I'm doing.

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And I'm just going to use n for new and partition number two, and enter for the first sector

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and push 2g to add a two gigabyte partition.

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Let's not forget, after adding the partition, you need to set the LVM partition type.

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So I'm using T on partition number two, to set the LVM partition type.

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And now before I'm leaving, I'm typing P, all looking good, and W to write.

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So at this point, I can use VG.

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Now, one little trick, if you are thinking about which utility do I need,

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as long as you remember you need to do something with the VG, use VG tab tab.

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And there you can see the VG extend utility.

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And this utility is very intuitive.

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You need the name of the VG, and you need the name of the device that you want to add.

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And now if I use VGS, you can see that I have about two gigs available on my storage device.

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So it's time for the next step, and that will be LV extend.

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So LV extend needs a couple of options.

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First, I need to specify that I want to extend dev VG data slash LV data.

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Very important, in most cases, is the option minus R,

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because minus R will resize the file system as well.

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It's not so useful if you make your logical volume bigger without growing the file system as well.

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And there are separate utilities.

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On XFS, it is XFS underscore grow FS.

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On EXC4, it is resize to FS that you can use to resize.

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Interesting to know, XFS can only be grown bigger.

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EXC4 can be reduced and extended in size.

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In most cases, you will want to extend, and that's exactly what I'm going to do here,

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using minus lowercase L plus 50% free.

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Now, this minus lowercase L is a nice option.

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You can also use it while you are creating your logical volumes.

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It allows you to give a relative size.

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Plus 50% free makes it I don't have to worry about the exact size that is available.

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I'm just going to add 50% of the available disk space.

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And there we can see it has found the EXC4 file system.

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It is doing the resize to 3 gigabytes, and then it is calling the resize to FS utility

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to automatically trigger the file system resize as well.

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And at the end of it, DF minus H is going to show us that the miracle has happened.

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Yay, we suddenly have 865 megabytes available on the file system,

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and we can continue working on it.

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And that's how you resize a logical volume.