12.2 Add Partitions, Logical Volumes, and Swap Non-Destructively

12.2 Add Partitions, Logical Volumes, and Swap Non-Destructively

Quick Answer: Add storage—do not wipe what already works. Create new partitions in free space, new LVs in VG free PE, and swap with mkswap + swapon + fstab UUID=. Verify with lsblk, lvs/vgs, swapon --show, and mount -a. Destroying existing data fails both the system and the objective.

Official skill

Under Configure local storage, EX200 expects you to add new partitions and logical volumes, and swap to a system non-destructively. The key word is non-destructively: grow the system’s usable storage without deleting or reformatting volumes that already contain required data.

Related skills you already use:

• GPT partitioning, PV/VG/LV create/delete (prior chapter)
• Mount by UUID/label (Section 12.1)
• Later: extend existing logical volumes and grow file systems (separate objective—do not confuse “add new LV” with “extend this LV and xfs_growfs”)

This section focuses on adding capacity and adding swap safely.

What “non-destructive” means on the exam

If a disk already has / or /home partitions, you do not rebuild the entire table from scratch. You inspect free space and add beside existing partitions.

Always inventory first

lsblk -f
lsblk -o NAME,SIZE,TYPE,FSTYPE,MOUNTPOINTS
findmnt
sudo pvs; sudo vgs; sudo lvs
cat /etc/fstab
free -h
swapon --show

Sketch what is already mounted and which VGs have free space (VFree in vgs). Only then plan the new partition, LV, or swap device.

Adding partitions non-destructively

New free space on an existing disk

1. Confirm free space: lsblk, sudo parted /dev/sdb print free (or gdisk/fdisk print).
2. Create a new partition only in the free region—do not delete partition 1 to “make room” if it still holds data.
3. Write the table, run partprobe or re-read as needed (udevadm settle, reboot only if the kernel will not re-read—prefer non-reboot methods first).
4. Optionally mkfs only on the new partition if the task wants a data FS (or mkswap if it is swap).
5. Persist mounts with UUID fstab (12.1).

sudo parted /dev/sdb print free
# Example: create a new primary partition in free space (sizes/names are task-specific)
sudo parted -s /dev/sdb mkpart primary xfs 20GiB 40GiB
sudo partprobe /dev/sdb
lsblk /dev/sdb
# New node might be /dev/sdb2 — confirm before mkfs
sudo mkfs.xfs /dev/sdb2
blkid /dev/sdb2

GPT vs legacy: RHEL 10 labs commonly use GPT. Match tools to the disk label already in use. Do not convert tables casually.

Entire new disk

A new unused disk (no existing partitions/data required by the system) can be partitioned from scratch on that disk only—still non-destructive relative to other disks. Never initialize the wrong disk (/dev/sda vs /dev/sdb).

lsblk
# Triple-check the device name before parted/mkfs

Adding logical volumes non-destructively

Non-destructive LVM addition usually means one of:

1. lvcreate a new LV in a VG that still has free physical extents.
2. Add a new PV (pvcreate on a new partition/disk) → vgextend an existing VG → lvcreate (or later extend an LV).

sudo vgs
# VG has free space? create new LV only:
sudo lvcreate -n lvdata -L 5G vgapp
sudo mkfs.xfs /dev/vgapp/lvdata
blkid /dev/vgapp/lvdata
sudo mkdir -p /data
# fstab UUID=... /data xfs defaults 0 0
sudo mount -a
findmnt /data

When the VG is full, extend the VG first without removing old PVs:

# New partition /dev/sdc1 dedicated as PV (created in free space / new disk)
sudo pvcreate /dev/sdc1
sudo vgextend vgapp /dev/sdc1
sudo vgs
sudo lvcreate -n lvlogs -L 2G vgapp

Do not vgremove vgapp just because you want another LV. Do not lvremove the root LV to free space. Free space comes from unused PE or new PVs.

lvcreate sizing reminders

sudo lvcreate -L 10G -n lv1 vg1          # exact size
sudo lvcreate -l 100%FREE -n lv2 vg1     # consume remaining PE (careful: leaves no free PE)
sudo lvcreate -l 50%FREE -n lv3 vg1

Prefer exact sizes from the task (5G, 512M). Using 100%FREE is fine when the task says “use all remaining space,” but it blocks later additive LVs until you add more PV space.

Adding swap non-destructively

Swap can be a partition, a logical volume, or less often a swap file. EX200 commonly uses a partition or LV. Steps:

1. Create the partition or LV without destroying other volumes.
2. mkswap initialize swap signature.
3. swapon activate immediately.
4. /etc/fstab entry for boot persistence (UUID preferred).
5. Verify with swapon --show and free -h.

Swap on a new partition

# After creating /dev/sdb3 as type linux-swap (or generic partition for swap)
sudo mkswap /dev/sdb3
blkid /dev/sdb3
# UUID="...." TYPE="swap"
sudo swapon /dev/sdb3
swapon --show
free -h

Swap on a new LV

sudo lvcreate -n swapvol -L 1G vg0
sudo mkswap /dev/vg0/swapvol
blkid /dev/vg0/swapvol
sudo swapon /dev/vg0/swapvol
swapon --show

fstab for swap

UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx  none  swap  defaults  0  0

Also acceptable in many systems:

UUID=...  swap  swap  defaults  0  0

Field meaning: type is swap; mount point is conventionally none or swap; dump and pass are 0 0 (never run fsck on swap as a normal FS).

Activate all fstab swap devices:

sudo swapon -a
swapon --show

Swap file (awareness)

sudo fallocate -l 1G /swapfile
# or dd if fallocate unsuitable on some FS
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
# fstab: /swapfile  none  swap  defaults  0  0

Prefer partition/LV when the task says “partition” or “logical volume.” Swap files are non-destructive to disks but still consume file-system space—do not place them carelessly on tiny root filesystems without reading the task.

Disable swap (only when needed)

sudo swapoff /dev/sdb3
sudo swapoff -a

Do not swapoff production swap during the exam unless you are resizing/replacing that swap device carefully.

Combining add + persistent mount

A full “add data storage” story often chains objectives:

new partition or LV → mkfs → UUID fstab mount (12.1) → mount -a → findmnt
new swap device → mkswap → UUID fstab swap → swapon -a → swapon --show

Non-destructive discipline applies at every step: only format new devices.

End-to-end exam scenarios

Scenario A — New 2G data LV, mounted at /data

sudo vgs
sudo lvcreate -n data -L 2G vgstorage
sudo mkfs.xfs /dev/vgstorage/data
UUID=$(blkid -s UUID -o value /dev/vgstorage/data)
sudo mkdir -p /data
echo "UUID=${UUID}  /data  xfs  defaults  0  0" | sudo tee -a /etc/fstab
sudo mount -a
findmnt /data

(Editing fstab with vim is equally valid—avoid duplicate lines.)

Scenario B — Add 512M swap LV that survives reboot

sudo lvcreate -n swap1 -L 512M vg0
sudo mkswap /dev/vg0/swap1
UUID=$(blkid -s UUID -o value /dev/vg0/swap1)
echo "UUID=${UUID}  none  swap  defaults  0  0" | sudo tee -a /etc/fstab
sudo swapon -a
swapon --show
free -h

Scenario C — New disk becomes PV; new LV without touching old LVs

lsblk
sudo parted -s /dev/sdd mklabel gpt mkpart primary 1MiB 100%
sudo pvcreate /dev/sdd1
sudo vgextend vgapp /dev/sdd1
sudo lvcreate -n newapp -L 10G vgapp
# old LVs unchanged — verify:
sudo lvs
findmnt

Scenario D — Free space partition for swap only

sudo parted /dev/sdb print free
# create partition in free space, type suitable for linux swap if your tool sets codes
sudo mkswap /dev/sdb2
sudo swapon /dev/sdb2
# fstab UUID line
sudo swapon -a

Verification checklist (use before leaving the station)

Optional reboot in practice labs confirms persistence; on timed exams, mount -a / swapon -a plus correct fstab is the standard pre-reboot proof.

Common traps

1. mkfs on the wrong device — erases existing data; always lsblk/blkid first.
2. Deleting partitions to recreate the disk when free space existed for an additive partition.
3. lvremove of the wrong LV to “free space” instead of adding a PV.
4. mkswap without fstab — swap works until reboot, then vanishes.
5. fstab device path for swap that renames after reboot—use UUID=.
6. Forgetting swapon after mkswap—free -h still shows old swap.
7. Duplicate UUIDs if you clone disks without re-making swap/FS UUIDs—regenerate with mkswap/xfs_admin -U only on the clone you intend to change.
8. Using 100%FREE for one LV when the task also requires a second new LV—plan sizes first.
9. Confusing this objective with LV extend — lvextend + xfs_growfs grows an existing FS; lvcreate adds a new volume. Read the task verb: add vs extend.
10. Wiping /etc/fstab while appending—back up or edit carefully so root still mounts.

Ordering relative to other chapters

Section checkpoint

You should inventory the system first, add partitions only in free space, add LVs with lvcreate (and vgextend when needed) without removing live volumes, build swap with mkswap/swapon/fstab UUID lines, verify with lsblk, lvs/vgs, findmnt, and swapon --show, and never run destructive format/remove commands on devices that already hold required data. That is the EX200 meaning of adding partitions, logical volumes, and swap non-destructively.