Boosting SAP HANA Disk I/O Performance on AWS
A company runs SAP HANA on AWS using a single EC2 instance with EBS volumes. The system experiences performance degradation during peak hours. Which approach would provide the MOST immediate improvement in disk I/O performance without downtime?
Quick Answer
The requirement here is the most immediate improvement without downtime, and that phrase is what narrows the field to a specific EBS capability: Elastic Volumes. Elastic Volumes let you modify an EBS volume's type, for example to gp3 or io2, and its provisioned IOPS while the volume remains attached and in use, with the change taking effect without detaching the volume or stopping the instance, which is exactly what immediate and without downtime require together. This is a meaningfully different mechanism from the other options: adding additional EBS volumes and configuring them into a RAID 0 array would require attaching new volumes and reconfiguring the storage layout, which involves downtime and operational work well beyond a simple online modification; migrating to a larger EC2 instance type improves compute resources like CPU and memory, but it doesn't change the performance characteristics of the existing disk I/O path, so it wouldn't directly fix an I/O bottleneck; and creating a new volume and copying data over with a tool like rsync inherently involves downtime during the cutover and doesn't provide an immediate fix. The general concept worth internalizing is that Elastic Volumes exists specifically to let you tune EBS performance, type and IOPS, live and in place, which makes it the go-to answer whenever a scenario asks for a fast, non-disruptive storage performance improvement rather than a larger architectural change.
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
✓
Modify the EBS volume type and IOPS using Elastic Volumes.
EBS Elastic Volumes allow modifying the volume type (e.g., to gp3 or io2) and IOPS online without detaching the volume or stopping the instance, providing immediate I/O improvement. Option A is incorrect because adding EBS volumes and configuring RAID 0 requires downtime and reconfiguration. Option B is incorrect because migrating to a larger instance type does not directly improve disk I/O; it improves compute performance. Option D is incorrect because creating a new volume and copying data with rsync involves downtime and does not provide immediate improvement.
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 additional EBS volumes and configure RAID 0 across them.
Why it's wrong here
Adding volumes and configuring RAID requires downtime and reconfiguration.
- ✗
Migrate the EC2 instance to a larger instance type.
Why it's wrong here
Instance migration requires stop/start, causing downtime, and may not directly improve disk I/O.
- ✓
Modify the EBS volume type and IOPS using Elastic Volumes.
Why this is correct
Elastic Volumes allow online modification of volume type and IOPS without downtime.
- ✗
Create a new EBS volume with higher performance and copy data using rsync.
Why it's wrong here
Copying data requires downtime or at least suspension of writes.
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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Same concept, more angles
1 more way this is tested on PAS-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is running SAP HANA on a memory-optimized EC2 instance with an EBS volume for /hana/data and /hana/log. The database administrator notices that the /hana/log volume is experiencing high write latency. The current volume is a gp2 volume with 1000 GB size. Which change would most effectively reduce write latency?
medium- A.Change the volume type to st1 (throughput optimized) for better write throughput.
- B.Increase the volume size to 2000 GB to get more IOPS.
- C.Enable Multi-Attach on the volume to distribute writes.
- ✓ D.Ensure the EC2 instance is EBS-optimized and use a higher instance type with dedicated EBS bandwidth.
Why D: Using EBS-optimized instances with dedicated EBS bandwidth reduces contention and latency, improving write performance for SAP HANA log. Option A is wrong because changing to st1 is not ideal for log writes; st1 is optimized for throughput, not low latency, and has variable performance. Option B is wrong because increasing volume size increases baseline IOPS for gp2 but does not directly address write latency; latency is influenced more by burst credits and instance EBS bandwidth. Option C is wrong because enabling Multi-Attach does not reduce latency; it allows multiple instances to attach the same volume but can introduce contention.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PAS-C01 practice question is part of Courseiva's free Amazon Web Services 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 PAS-C01 exam.