Creating a SWAP partition in a LVM

Assuming that you have already created a physical volume ==> volume group.

If not then click here.....

Now firstly create a logical volume.

Check the free space in your volume group by firing a command in terminal as vgdisplay VOLUMEGROUP NAME.


[root@sunny ~]# vgdisplay vg_sunny
  --- Volume group ---
  VG Name               vg_sunny
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               14.51 GiB
  PE Size               4.00 MiB
  Total PE              3714
  Alloc PE / Size       3204 / 12.52 GiB
  Free  PE / Size       510 / 1.99 GiB
  VG UUID               XdBCWB-sQw5-JQvn-v0an-VOWi-fIs9-Q7uEmm

This command shows that in this volume group we still have a free space of 1.99GB.

Now we need to create a logical volume by the help of lvcreate command.

[root@sunny ~]# lvcreate -L 100M -n lv-swap-new vg_sunny

  Logical volume "lv-swap-new" created

Now just format the newly created logical volume to swap.

[root@sunny ~]# mkswap /dev/vg_sunny/lv-swap-new 

mkswap: /dev/vg_sunny/lv-swap-new: warning: don't erase bootbits sectors

        on whole disk. Use -f to force.

Setting up swapspace version 1, size = 102396 KiB

no label, UUID=0bac54cc-eff5-4f6d-af00-f82b83132a20

Now you have successfully created your swap partition now for using this what you need to do is just enable that swap partition.

Firstly check the amount of swap space which is presently allocated to your machine's OS.

[root@sunny ~]# free -m

             total       used       free     shared    buffers     cached

Mem:          1506        575        930          0         24        275

-/+ buffers/cache:        275       1230

Swap:          999          0        999

You can do this either via free -m or via swapon -s commands.

[root@sunny ~]# swapon -s

Filename Type Size Used Priority

/dev/dm-1                               partition 1023992 0 -1

Just switch the new swap device on:

[root@sunny ~]# swapon /dev/vg_sunny/lv-swap-new 

Now just to verify that your new partition has been activated or not just fire the same command swapon -s (-s is for summary of all your swap partitions).

[root@sunny ~]# swapon -s

Filename Type Size Used Priority

/dev/dm-1                               partition 1023992 0 -1

/dev/dm-2                               partition 102392 0 -2

Summary: Previously your swap partition which was allocated to your machine was 999MB but now you have a swap space which is allocated to your machine is 1099MB which can be switched on or switched off as per your requirements.

Now suppose that you need to switch off your swap space which you just created, so for doing that what you need to so is just fire swapoff.

[root@sunny ~]# swapoff /dev/vg_sunny/lv-swap-new 

[root@sunny ~]# swap -s

-bash: swap: command not found

[root@sunny ~]# swapon -s

Filename Type Size Used Priority

/dev/dm-1                               partition 1023992 0 -1

[root@sunny ~]# 

Don't forget to add entry of new swap space in /etc/fstab file.