RHCSA Practical Lab Series – Adding a Swap Partition

🔍 Lab 19: Configuring a Swap Partition in RHEL 9

📌 Objective

In this lab, you will:

✔ Create a new 512 MiB swap partition
✔ Format it as swap space
✔ Configure the system to automount swap at boot

📌 Step 1: Identify Available Disks and Partitions

🔹 List the current disk layout:

[root@node2 ~]# lsblk

📌 Expected Output (Example):

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda    252:0    0   20G  0 disk
├─vda1 252:1    0    1G  0 part /boot
└─vda2 252:2    0   19G  0 part /
vdb    252:16   0    5G  0 disk

✅ Ensure vdb is available before proceeding.

📌 Step 2: Create a Swap Partition

🔹 Use fdisk to create a new partition:

[root@node2 ~]# fdisk /dev/vdb

📌 Inside the fdisk prompt, perform the following:

1. Press n → Create a new partition.
2. Press p → Make it a primary partition.
3. Press 3 → Assign partition number 3.
4. Press Enter twice → Accept the default start and end sectors.
5. Press t → Change partition type.
6. Enter 82 → Set the type to Linux swap.
7. Press w → Write changes and exit.

✅ Re-run lsblk to confirm the partition exists as /dev/vdb3.

📌 Step 3: Format the Partition as Swap

🔹 Run the mkswap command to format the partition:

[root@node2 ~]# mkswap /dev/vdb3

✅ Expected Output:

Setting up swapspace version 1, size = 512 MiB

🔹 Enable the swap partition immediately:

[root@node2 ~]# swapon /dev/vdb3

✅ Verify if swap is active:

[root@node2 ~]# free -h

📌 Expected Output:

              total        used        free
Mem:          3.8G        1.2G        2.6G
Swap:         512M          0B        512M

✅ If Swap shows 512M, the swap is successfully added.

📌 Step 4: Persist Swap Across Reboots

🔹 Add the swap entry to /etc/fstab:

[root@node2 ~]# vim /etc/fstab

🔹 Append this line at the end:

/dev/vdb3 swap swap defaults 0 0

✅ Save and exit (ESC + :wq).

🔹 Reload the fstab file and verify:

[root@node2 ~]# swapon -a
[root@node2 ~]# swapon --show

📌 Expected Output:

NAME       TYPE  SIZE USED PRIO
/dev/vdb3  swap 512M   0B   -2

✅ If /dev/vdb3 appears, the swap is correctly configured.

📌 Step 5: Verify After Reboot (Optional)

🔹 Reboot the system:

[root@node2 ~]# reboot

🔹 After reboot, confirm swap is active:

[root@node2 ~]# free -h

✅ If Swap still shows 512M, everything is correctly set!

📌 Troubleshooting Tips

🔹 If the swap partition does not mount after reboot, check /etc/fstab syntax:

[root@node2 ~]# cat /etc/fstab

🔹 If mkswap fails, ensure the partition type is 82 (Linux swap):

[root@node2 ~]# fdisk -l /dev/vdb

🔹 To disable swap temporarily:

[root@node2 ~]# swapoff -a

🔹 To remove swap permanently, delete the line from /etc/fstab and turn swap off.

✅ Final Summary

✔ Created a 512 MiB swap partition on /dev/vdb3
✔ Formatted it using mkswap
✔ Enabled swap immediately using swapon
✔ Persisted swap configuration in /etc/fstab
✔ Verified swap functionality after a system reboot

📌 Next Lab: Configuring Logical Volumes in RHEL 9

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