====== Create a new swap ======

Creating an LVM2 Logical Volume for Swap

To add a swap volume group (assuming /dev/VolGroup00/LogVol02 is the swap volume you want to add):

Create the LVM2 logical volume of size 256 MB:
<cli prompt='#'>
# lvcreate -L 1G -n LogVol02 VolGroup00 
</cli>

Format the new swap space:
<cli prompt='#'>
# mkswap /dev/VolGroup00/LogVol02
</cli>

Add the following entry to the /etc/fstab file:
  /dev/VolGroup00/LogVol02   swap     swap    defaults     0 0

Enable the extended logical volume:
<cli prompt='#'>
# swapon -va
</cli>

Test that the logical volume has been extended properly:
<cli prompt='#'>
# cat /proc/swaps # free
</cli>

<cli prompt='#'>
swapoff /dev/hda3
mkswap /dev/hda4
swapon /dev/hda4
</cli>

and edit swap entry in /etc/fstab

==== How to Increase Swap Space in Linux? ====

Check the current swap space
<cli prompt='#'>
[root@lnxb080 etc]# free -h
              total        used        free      shared  buff/cache   available
Mem:          7.4Gi       1.4Gi       784Mi       384Mi       5.3Gi       5.0Gi
Swap:         2.0Gi       211Mi       1.8Gi

[root@lnxb080 ~]# swapon --show
NAME      TYPE      SIZE   USED PRIO
/dev/dm-6 partition   2G 211.4M   -2

[root@lnxb080 ~]# ll /dev/dm-6
brw-rw---- 1 root disk 253, 6 Jan  8 21:00 /dev/dm-6

[root@lnxb080 ~]# lsblk
NAME                     MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda                        8:0    0   40G  0 disk
├─sda1                     8:1    0   10M  0 part
├─sda2                     8:2    0 1005M  0 part
├─sda3                     8:3    0   39G  0 part
└─mpathd                 253:0    0   40G  0 mpath
  ├─mpathd1              253:2    0   10M  0 part
  ├─mpathd2              253:3    0 1005M  0 part  /boot
  └─mpathd3              253:4    0   39G  0 part
    ├─rootvg-root        253:5    0    3G  0 lvm   /
    ├─rootvg-swap        253:6    0    2G  0 lvm   [SWAP]
    ├─rootvg-usr         253:7    0    3G  0 lvm   /usr
</cli>

Disable the swap
<cli prompt='#'>
# swapoff -v /dev/{swap_partition}
</cli>

Resize the partition

Format the ne swap space
<cli prompt='#'>
# mkswap /dev/{swap_partition}
</cli>

Enable the swap
<cli prompt='#'>
# swapon /dev/{swap_partition}
</cli>

Check fstab
<cli prompt='#'>
[root@lnxb080 etc]# cat fstab
...
/dev/mapper/rootvg-swap none                    swap    defaults        0 0
</cli>

==== Creating a Swap File (instead of partition) ====

Create the swap file with 4GB
<cli prompt='#'>
# fallocate -l 4G /swap/swapfile01
or
# mkswap -U clear --size 4G --file /swap/swapfile01
</cli>

Change the permissions
<cli prompt='#'>
# chmod 600 /swap/swapfile01
</cli>

Format the swap
<cli prompt='#'>
# mkswap /swap/swapfile01
</cli>

Add to /etc/fstab
  /swapfile none swap defaults 0 0