Скачать или смотреть Redhat Linux 9 Lab: Exercise 15-3 Resizing Logical Volumes

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2023 08 25 06 20 34


Exercise 15-3 Resizing Logical Volumes In Exercises 15-1 and 15-2, you created a physical volume, volume group, and logical volume. In this exercise, you extend
the size of the logical volume and the file system used on top of it. 1. Type pvs and vgs to show the current physical volume and volume group configuration. 2. Use lsblk to verify that you have an unused partition available that can be added to the volume group. In Exercise 15-1 you created the partition /dev/sdd2 for this purpose. 3. Type vgextend vgdata /dev/sdd2 to extend vgdata with the total size of the /dev/sdd2 device. 4. Type vgs to verify that the available volume group size has increased. 5. Type lvs to verify the current size of the logical volume lvdata. 6. Type df -h to verify the current size of the file system on lvdata. 7. Type lvextend -r -l +50%FREE /dev/vgdata/lvdata to extend lvdata with 50% of all available disk space in the volume group. 8. Type lvs and df -h again to verify that the added disk space has become available.

To grow the logical volume size, use lvextend or lvresize, followed by the -r option to resize the file system used on it. Then specify the size you want the resized volume to be. The easiest and most intuitive way to do that is by using -L followed by a + sign and the amount of disk space you want to add, as in lvresize -L +1G -r /dev/vgdata/lvdata. An alternative way to resize the logical volume is by using the -l option. This option is followed either by the number of extents that are added to the logical volume or by the absolute or relative percentage of
extents in the volume group that will be used. You can, for example, use the following commands to resize the logical volume: lvresize -r -l 75%VG /dev/vgdata/lvdata Resizes the logical volume so that it will take 75% of the total disk space in the volume group. Notice that if currently the logical volume is using more than 75% of the volume group disk space, this command will try to reduce the logical volume size! lvresize -r -l +75%VG /dev/vgdata/lvdata Tries to add 75% of the total size of the volume group to the logical volume. This will work only if currently at least 75% of the volume group is unused. (Notice the difference with the previous command.)
lvresize -r -l +75%FREE /dev/vgdata/lvdata Adds 75% of all free disk space to the logical volume. lvresize -r -l 75%FREE /dev/vgdata/lvdata Resizes the logical volume to a total size that equals 75% of the amount of free disk space, which may result in an attempt to reduce the logical volume size. (Notice the difference with the previous command.)
A logical extent is the logical building block used when creating logical volumes, and it maps to a physical extent, the size of which can be specified when creating a volume group. All resize operations need to match complete logical extents. You will sometimes notice that the resize size is rounded up or down to the logical extent size. You can also specify the number of logical extents that need to be added or removed directly by using the -l option with the lvresize command. As you can see, resizing a logical volume has many options, and you need to take care to use the right options because it is easy to make a mistake! In Exercise 15-3, you learn how to resize logical volumes and the file systems used on top of them. Note The size of an XFS file system cannot be decreased; it can only be increased. If you need a file system that can be shrunk in size, use Ext4, not XFS.