Logical Volume Manager

Question 1

What is a physical volume?

Answer 1

Underlying physical storage unit used by LVM
Can use partition or entire block device
*partition type must be initialised/marked as Linux LVM to provide metadata to LVM

Question 2

What is the structure for LVM?

Answer 2

── Logical Volume
└── Volume Group
├─── Physical Volume 1
└─── Physical Volume 2

Question 3

What is an extent in a Volume Group?

Answer 3

Smallest amount of space that can be assigned to a volume group, also knows as physical extents. They are mapped to logical volumes

Question 4

How do you create a Physical Volume?

Answer 4

pvcreate {/block/device}

Question 5

How do you view Physical Volumes on the system?

Answer 5

pvdisplay

Question 6

How do you create a Volume Group?

Answer 6

vgcreate {vgname} {/physical/volume}

Question 7

How do you view Volume Groups on the system?

Answer 7

vgdisplay

Question 8

How do you create a Logical Volume?

Answer 8

lvcreate -n {name} -L {size} {vgname}

Question 9

How do you view Logical Volumes?

Answer 9

lvdisplay

Question 10

On a Logical Volume what are the limitations of xfs vs ext4?

Answer 10

LVM using xfs can only be increased

LVM using ext4 can be increased and decreased

Question 11

How do you delete a Physical Volume?

Answer 11

pvremove

Question 12

How do you delete a Volume Group?

Answer 12

vgremove

Question 13

How do you delete a Logical Volume?

Answer 13

lvremove

Question 14

How do you format an LVM to be used as swap space?

Answer 14

mkswap {/lv/path}

i. e mkswap /dev/vg1/lvswap1
* formats with swap signature

Question 15

How do you mount a swap disk?

Answer 15

swapon

i.e swapon /dev/vg1/lvswap1

Question 16

How do you unmount a swap disk?

Answer 16

swapoff

i.e swapoff /dev/vg1/lvswap1

Question 17

How do you persistently mount swap a disk?

Answer 17

Edit /etc/fstab
UUID, /block/device
specify path and filetype of: swap

Question 18

How do you mount all swap disk entries listed in /etc/fstab?

Answer 18

swapon -a

Question 19

How do you format a partition/volume for swap?

Answer 19

mkswap {/block/device}

Partition must have an id type of Linux swap

Question 20

How do you get a summary about used swap devices?

Answer 20

swapon -s

*also located in /proc/swaps

Question 21

How do you add another block device to a volume group?

Answer 21

vgextend {vgname} {/physical/volume}

Question 22

If there are multiple block devices in a volume group, how do you move the data from one physical volume to others within the group so that it can be removed?

Answer 22

pvmove {/block/device}
Physical extents on the device will be copied to other physical volumes
*useful if changing partition format MBR vs GPT

Question 23

How do you remove a physical volume from a volume group?

Answer 23

vgreduce {vgname} {/physical/volume}

Question 24

How do you extend a logical volume?

Answer 24

lvextend {lvname} -L {size}

Question 25

Once a logical volume is extended how do you increase the filesystem size?

Answer 25

xfs: xfs_growfs {/mount/point}
ext4: resize2fs {/mount/point}
* lv must be mounted to see filesystem