LFCS Storage Management Practice Question
An administrator has added a new disk (/dev/sdb) to a Linux system. The disk is to be used as a physical volume in an existing volume group 'vg_data'. Which sequence of commands should be executed to make the disk available to the volume group?
⚠ Common exam trap
It's easy for candidates to think partitioning (fdisk) is required before LVM operations, or confuse `vgcreate` (which creates a new VG) with `vgextend` (which adds to an existing VG), leading them to pick options that either perform unnecessary steps or use the wrong command for the task.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
pvcreate /dev/sdb; vgextend vg_data /dev/sdb
It first initializes the disk as a physical volume using `pvcreate`, which writes LVM metadata to /dev/sdb, and then extends the existing volume group 'vg_data' with `vgextend`, adding the new PV to the VG. This is the standard two-step process for adding a new disk to an existing LVM volume group.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
fdisk /dev/sdb; pvcreate /dev/sdb; vgextend vg_data /dev/sdb
Why it's wrong here
Partitioning with fdisk is unnecessary here: pvcreate and vgextend work directly on the whole disk, so the extra step adds nothing and may leave the disk partitioned rather than used whole. It is tempting because fdisk is the standard tool when a specific partition, not the raw device, must back the physical volume.
- ✓
pvcreate /dev/sdb; vgextend vg_data /dev/sdb
Why this is correct
pvcreate initialises /dev/sdb as an LVM physical volume, writing the metadata header LVM requires before any volume group can claim it. vgextend then adds that PV to the existing vg_data, extending its capacity without recreating the group or disturbing existing logical volumes.
- ✗
pvcreate /dev/sdb; vgcreate vg_data /dev/sdb
Why it's wrong here
vgcreate builds a new volume group, so running it against vg_data either fails because the group already exists or creates a duplicate name, and the disk never joins the existing group. It is tempting because vgcreate is the genuine tool for initialising a volume group, which would be right when no vg_data existed yet.
- ✗
vgcreate /dev/sdb; vgextend vg_data /dev/sdb
Why it's wrong here
vgcreate expects a volume group name, not a block device, so passing /dev/sdb fails outright and no physical volume is initialised. It is tempting because vgcreate and vgextend are the real LVM group commands, and vgcreate would be correct when creating a brand-new volume group from scratch.
Go deeper
Related to this question
About these practice questions
This LFCS question is part of Courseiva's 406-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.