220-1101 - Hardware and Network Troubleshooting (29% of the exam) - Section 5.3

Troubleshoot and diagnose problems with storage drives and RAID arrays in a given scenario.

Diagnose storage faults from symptoms such as read/write failures, slow performance, clicking or grinding noises, S.M.A.R.T. failures, and a degraded or failed RAID array, and recognise when data is recoverable versus lost. Distinguish a drive controller or cable fault from media failure, and verify with appropriate tools before deciding whether to rebuild the array or restore from backup.

S.M.A.R.T. failureRAID array failureRead/write failureDrive clicking noise

Practice question for this objective

Free sampleHardware and Network Troubleshootinghard

A three-drive RAID 5 array on a small server has lost one member drive. The operating system is still running and the array reports a degraded but online state. A matching replacement drive is on hand. What is the BEST action to restore full redundancy?

AReplace the failed member and let the controller rebuild the missing data from the distributed parity while the array stays online. Correct
BRecreate the array from scratch, because RAID 5 cannot recover from the loss of any single member drive without a full reinitialisation.
CDo nothing, since RAID 5 mirrors every block and the surviving drives already hold a complete duplicate copy of the data.
DConvert the degraded array to RAID 0 to restore full performance until a proper replacement drive can be sourced later.

Know that a degraded RAID 5 array recovers by replacing the failed drive and rebuilding lost data from distributed parity. RAID 5 stripes data with one distributed parity block per stripe, tolerating a single drive failure; installing a replacement lets the controller recompute the missing blocks from parity and the surviving data, returning the array to a fault-tolerant state.

Why A is correct: RAID 5 tolerates one drive loss; inserting a replacement lets the controller reconstruct the lost blocks from parity spread across the surviving members, restoring redundancy without downtime.

Why B is wrong: Recreating the array is a real procedure, but RAID 5 is specifically designed to survive one failure via parity, so wiping and rebuilding would needlessly destroy recoverable data.

Why C is wrong: This confuses RAID 5 with RAID 1; RAID 5 uses distributed parity, not mirroring, and a degraded array has no redundancy left, so ignoring it risks total loss on a second fault.

Why D is wrong: RAID 0 does boost performance, but converting to it abandons all redundancy and typically requires rebuilding the set, leaving the data even more exposed than it already is.

See more 220-1101 practice questions, answers explained.

Exam traps in Hardware and Network Troubleshooting

Answers that look right on this material and are not. Each one is a distractor from a different question in the 220-1101 bank for this domain.

The replacement drive was smaller than the original member, so parity could not be recalculated across the full set of drives.
Why it is wrong: A too-small replacement is a real cause of a rebuild refusing to start, but here the rebuild began and then failed on a different drive, which points to a fault on a surviving member.
Run chkdsk to repair the file system and keep using the drive, since a clicking noise is only a cosmetic cooling-fan issue.
Why it is wrong: Tempting because chkdsk does fix logical file-system errors, but a mechanical click is not a fan and chkdsk cannot repair failing read/write heads, so continued use risks total data loss.
Immediately hot-swap the flagged drive so the controller can rebuild onto a fresh disk at once.
Why it is wrong: Replacing the drive feels decisive, but starting a rebuild with no backup risks a second-member unrecoverable read error during the parity rebuild, which would collapse the whole array.

Examworthy is not affiliated with or endorsed by CompTIA. Original, blueprint-aligned practice material only.