LPIC-2 Practice Question: Block Devices, Filesystems and Advanced Storage
A database server experiences performance degradation. Analysis shows high I/O wait on a LVM logical volume that uses striping across two physical volumes. What is the most effective way to improve performance?
⚠ Common exam trap
It's easy for candidates to assume striping alone maximizes performance, but they overlook that high I/O wait is often due to random access latency, which a cache layer directly mitigates without requiring a disruptive reconfiguration.
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
✓
Add a cache layer using lvmcache on a fast SSD
Adding a cache layer using lvmcache on a fast SSD is the most effective way to reduce high I/O wait because it places frequently accessed (hot) data on the faster SSD while keeping the bulk of data on the slower striped HDDs. This directly addresses the I/O bottleneck without requiring data migration or downtime, and it leverages the existing striped layout for sequential throughput while improving latency for random reads/writes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Add a cache layer using lvmcache on a fast SSD
Why this is correct
Caching with SSDs accelerates reads and writes, reducing I/O wait.
- ✗
Increase the stripe size and recreate the LV
Why it's wrong here
Increasing stripe size might help for large sequential I/O but requires recreation and does not solve the root issue of slow disks.
- ✗
Add an additional PV to the VG and extend the LV
Why it's wrong here
Adding more PVs may distribute load but does not address high I/O wait due to slow disks.
- ✗
Convert the LV to use linear mapping instead of striping
Why it's wrong here
Striping improves parallelism; converting to linear would worsen performance.
Quick reference
RAID Level Comparison
| RAID Level | Min Disks | Fault Tolerance | Read | Write | Usable Capacity |
|---|---|---|---|---|---|
| RAID 0 | 2 | None | Excellent | Excellent | 100% |
| RAID 1 | 2 | 1 disk | Good | Moderate | 50% |
| RAID 5 | 3 | 1 disk | Good | Moderate | 67–94% |
| RAID 6 | 4 | 2 disks | Good | Lower | 50–88% |
| RAID 10 | 4 | 1 disk per mirror | Excellent | Good | 50% |
RAID is not a backup strategy — it protects against disk failure but not against accidental deletion, ransomware, or site-level events.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-2 practice question is part of Courseiva's free LPI 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 LPIC-2 exam.