How To Create/Extend Swap Partition In Linux Using LVM

https://www.2daygeek.com/how-to-create-extend-swap-partition-in-linux-using-lvm/

BY RAMYA NUVVULA · PUBLISHED : MARCH 28, 2018 || LAST UPDATED: MARCH 28, 2018

 

We are using LVM for flexible volume management so, why can’t we use LVM for swap space?

This allow users to increase the swap partition whenever we need.

If you upgraded the RAM in your system, it is necessary to add more swap space.

This help you to manage the system that run applications that require a large amount of memory.

Swap can be created in three ways

• Create a new swap partition
• Create a new swap file
• Extend swap on an existing logical volume (LVM)

It’s recommended to create a dedicated swap partition instead of swap file.

Suggested Read :
(#) 3 Easy Ways To Create Or Extend Swap Space In Linux
(#) Automatically Create/Remove And Mount Swap File In Linux Using Shell Script

What is the recommended swap size in Linux?

What Is Swap Space

Swap space in Linux is used when the amount of physical memory (RAM) is full. When physical RAM is full, inactive pages in memory are moved to the swap space.

This helps system to run the application continuously but it’s not considered a replacement for more RAM.

Swap space is located on hard drives so, it would not processing the request like physical RAM.

How To Create A Swap Partition Using LVM

As we already know how to create logical volume do the same for swap as well. Just follow the below procedure.

Create a logical volume which you required. In my case i’m going to create 5GB of swap partition.

$ sudo lvcreate -L 5G -n LogVol_swap1 vg00
  Logical volume "LogVol_swap1" created.

Format the new swap space.

$ sudo mkswap /dev/vg00/LogVol_swap1
Setting up swapspace version 1, size = 5 GiB (5368705024 bytes)
no label, UUID=d278e9d6-4c37-4cb0-83e5-2745ca708582

Add the following entry to the /etc/fstab file.

# vi /etc/fstab
/dev/mapper/vg00-LogVol_swap1   swap     swap    defaults     0 0

Enable the extended logical volume.

$ sudo swapon -va
swapon: /swapfile: already active -- ignored
swapon: /dev/mapper/vg00-LogVol_swap1: found signature [pagesize=4096, signature=swap]
swapon: /dev/mapper/vg00-LogVol_swap1: pagesize=4096, swapsize=5368709120, devsize=5368709120
swapon /dev/mapper/vg00-LogVol_swap1

Test that the swap space has been added properly.

$ cat /proc/swaps
Filename				Type		Size	Used	Priority
/swapfile                               file		1459804	526336	-1
/dev/dm-0                               partition	5242876	0	-2

$ free -g
              total        used        free      shared  buff/cache   available
Mem:              1           1           0           0           0           0
Swap:             6           0           6

How To Expand A Swap Partition Using LVM

Just follow the below procedure to extend an LVM swap logical volume.

Disable swapping for the associated logical volume.

$ sudo swapoff -v /dev/vg00/LogVol_swap1
swapoff /dev/vg00/LogVol_swap1

Resize the logical volume. I’m going to increase the swap volume from 5GB to 11GB.

$ sudo lvresize /dev/vg00/LogVol_swap1 -L +6G
  Size of logical volume vg00/LogVol_swap1 changed from 5.00 GiB (1280 extents) to 11.00 GiB (2816 extents).
  Logical volume vg00/LogVol_swap1 successfully resized.

Format the new swap space.

$ sudo mkswap /dev/vg00/LogVol_swap1
mkswap: /dev/vg00/LogVol_swap1: warning: wiping old swap signature.
Setting up swapspace version 1, size = 11 GiB (11811155968 bytes)
no label, UUID=2e3b2ee0-ad0b-402c-bd12-5a9431b73623

Enable the extended logical volume.

$ sudo swapon -va
swapon: /swapfile: already active -- ignored
swapon: /dev/mapper/vg00-LogVol_swap1: found signature [pagesize=4096, signature=swap]
swapon: /dev/mapper/vg00-LogVol_swap1: pagesize=4096, swapsize=11811160064, devsize=11811160064
swapon /dev/mapper/vg00-LogVol_swap1

Test that the logical volume has been extended properly.

$ free -g
              total        used        free      shared  buff/cache   available
Mem:              1           1           0           0           0           0
Swap:            12           0          12

$ cat /proc/swaps
Filename				Type		Size	Used	Priority
/swapfile                               file		1459804	237024	-1
/dev/dm-0                               partition	11534332	0	-2