220-1101 Storage and RAID Troubleshooting — Timed 20 Questions

Question 1

A technician is building a workstation for video editing and needs to install two M.2 NVMe SSDs. The motherboard has one M.2 slot that supports both SATA and NVMe, and another that supports only SATA. When the technician installs both drives, only the NVMe drive is detected. What is the most likely reason?

Accepted Answer

The second M.2 slot only supports SATA SSDs, not NVMe.. M.2 slots can have different interface support. If one slot only supports SATA, an NVMe SSD will not be recognized. This tests knowledge of M.2 slot compatibility.

Answer

The NVMe drive is not properly seated.

Answer

The BIOS needs to be updated.

Answer

The SATA SSD is defective.

Question 2

A technician is configuring a new NAS with four 10 TB hard drives. The customer wants maximum usable capacity with fault tolerance for one drive failure. The technician sets up RAID 5, but after initialization, the usable capacity is only 10 TB instead of the expected 30 TB. What is the most likely cause?

Accepted Answer

The array was accidentally configured as RAID 1 (mirroring) across two drives.. RAID 5 with four drives of equal size should yield (n-1) * capacity = 30 TB. A 10 TB result suggests only two drives are being used, possibly due to a misconfiguration like RAID 1 or a stripe set of two drives. This tests RAID 5 capacity calculation and troubleshooting.

Answer

One of the drives is defective and the array is using only three drives.

Answer

The drives are not all the same size; one is 5 TB.

Answer

The RAID controller is using a different stripe size.

Question 3

A technician is troubleshooting a server that uses a hardware RAID controller with a 1 GB cache. The server experiences periodic write performance drops, and the event log shows 'Cache battery low' warnings. What is the most likely impact of this condition?

Accepted Answer

The controller will disable write caching to protect data integrity.. RAID controllers use cache batteries to protect data in write cache during power loss. When the battery is low, the controller may disable write caching to prevent data loss, causing write performance to drop. This tests knowledge of RAID controller cache behavior.

Answer

The controller will switch to read-only mode.

Answer

The controller will increase the stripe size to compensate.

Answer

The controller will automatically rebuild the array.

Question 4

A small business server with a RAID 10 array of four 2 TB hard drives experiences a drive failure. The technician replaces the failed drive with an identical model. After rebuilding, the array reports as healthy, but the total capacity is now 2 TB instead of the expected 4 TB. What is the most likely cause?

Accepted Answer

The array was accidentally rebuilt as a RAID 1 mirror instead of RAID 10.. RAID 10 combines mirroring and striping. If the replacement drive is not properly sized or the array is misconfigured, capacity can be incorrect. However, the most common cause is using a drive with different geometry or the array being rebuilt as a single mirror instead of striped mirrors. This question tests understanding of RAID 10 capacity calculation.

Answer

The replacement drive has a different sector size.

Answer

The new drive is 1 TB instead of 2 TB.

Answer

The array is using a non-standard stripe size.

Question 5

A user complains that their external USB hard drive is not recognized when plugged into a Windows 10 workstation. The technician checks Device Manager and sees an unknown device with a yellow exclamation mark. What should the technician do first?

Accepted Answer

Update the driver for the unknown device.. A yellow exclamation mark in Device Manager typically indicates a driver issue. The first logical step is to update or reinstall the driver for the unknown device. This tests basic USB troubleshooting.

Answer

Replace the USB cable.

Answer

Format the external drive.

Answer

Disable the USB root hub in Device Manager.

Question 6

A technician is troubleshooting a desktop that fails to boot and displays 'No bootable device' after a power outage. The system has a single SATA SSD for the OS and a separate HDD for data. The BIOS detects both drives. What should the technician check first?

Accepted Answer

Check the boot order in BIOS/UEFI.. After a power outage, the boot order in BIOS can reset to defaults, causing the system to try booting from the wrong drive. This tests understanding of BIOS/UEFI boot settings.

Answer

Replace the SATA cable for the SSD.

Answer

Run a CHKDSK on the HDD.

Answer

Replace the CMOS battery.

Question 7

A customer reports that their computer with a RAID 5 array is running very slowly during file transfers. The system uses three 1 TB SATA hard drives. The technician runs a diagnostic and finds that one drive has a high number of reallocated sectors. What is the most likely cause of the performance issue?

Accepted Answer

One of the drives is failing and the array is operating in degraded mode.. In a RAID 5 array, if one drive is failing (e.g., high reallocated sectors), the array may still be operational but performance degrades significantly because the controller must reconstruct data on the fly from parity information. This scenario tests understanding of RAID 5 behavior during drive degradation.

Answer

The RAID controller is overheating.

Answer

The array is configured with the wrong stripe size.

Answer

The operating system is defragmenting the array.

Question 8

A user reports that their RAID 5 array with three 2 TB drives is missing one drive in the RAID configuration utility. The technician finds that the missing drive is not detected by the system BIOS. What should the technician do next?

Accepted Answer

Check the SATA cable and power connection to the missing drive.. If a drive is not detected in BIOS, the issue is at the hardware level—cable, power, or drive failure. The next step is to check connections. This tests systematic troubleshooting of RAID hardware.

Answer

Initialize the missing drive in Disk Management.

Answer

Replace the RAID controller.

Answer

Rebuild the array using the remaining two drives.

Question 9

A technician is called to a data center where a server with a RAID 6 array of six 8 TB drives has experienced a double drive failure. The technician replaces both failed drives. After the rebuild, the array reports as healthy but the performance is extremely slow during normal operations. What is the most likely cause?

Accepted Answer

The array is still rebuilding in the background, consuming I/O resources.. After a rebuild, the array may be performing a background consistency check or initialization that consumes I/O resources. RAID 6 rebuilds are intensive, and the controller may be verifying parity. This tests advanced RAID troubleshooting.

Answer

The new drives have a different rotational speed.

Answer

The RAID controller cache battery is dead.

Answer

The stripe size was changed during the rebuild.

Question 10

A technician is setting up a new file server with four 4 TB SATA SSDs. The customer requires maximum read performance and fault tolerance for up to two drive failures. Which RAID level should the technician choose?

Accepted Answer

RAID 6. RAID 6 stripes data and uses dual parity, allowing up to two drive failures while maintaining good read performance. This question tests knowledge of RAID levels and their fault tolerance capabilities.

Answer

RAID 0

Answer

RAID 1

Answer

RAID 5

Question 11

A server with a RAID 6 array of six 2 TB drives experiences a double drive failure. After replacing both drives, the technician starts the rebuild process, but the array status shows 'Degraded' and the rebuild fails. What is the most likely cause?

Accepted Answer

A third drive has developed bad sectors.. RAID 6 can tolerate two drive failures, but if a third drive fails or has bad sectors during rebuild, the array may fail. The most likely cause is that a third drive developed bad sectors during the rebuild, preventing successful reconstruction. This highlights the risk of rebuild stress on older drives.

Answer

The new drives are not the same capacity as the originals.

Answer

The RAID controller firmware is outdated.

Answer

The rebuild process was interrupted by a power outage.

Question 12

After installing a second hard drive in a desktop PC, the system boots but the new drive does not appear in File Explorer. The drive is listed in Disk Management as 'Unknown' and 'Not Initialized'. What should the technician do first?

Accepted Answer

Initialize the disk in Disk Management.. This scenario tests initial steps for adding a new storage device. The drive must be initialized and partitioned before it can be used. The correct first step is to initialize the disk using a partition style like GPT or MBR.

Answer

Replace the SATA cable.

Answer

Format the drive immediately.

Answer

Update the motherboard chipset drivers.

Question 13

A technician is configuring a RAID 10 array for a database server using four 500 GB SSDs. After setup, the array shows a total capacity of 1 TB instead of 2 TB. What is the most likely reason for this discrepancy?

Accepted Answer

RAID 10 uses half the total capacity for mirroring.. RAID 10 combines mirroring (RAID 1) and striping (RAID 0). With four drives, two mirrored pairs are created, so half the capacity is used for redundancy. The total usable capacity is (number of drives / 2) * drive size, which is 1 TB in this case.

Answer

The RAID controller is faulty.

Answer

The array was accidentally configured as RAID 1.

Answer

The drives are not all the same size.

Question 14

A small office server uses RAID 5 with three 1 TB hard drives. One drive fails and is replaced with a new 1 TB drive. During the rebuild process, the server becomes very slow and the RAID controller reports an error. What is the most likely cause of the slowdown?

Accepted Answer

The rebuild process is consuming all available disk I/O.. RAID 5 rebuilds require reading data from all remaining drives to reconstruct parity, which consumes significant I/O resources. This can cause performance degradation, especially if the array is in use during rebuild. The error may also indicate a second drive failure or a bad sector.

Answer

The new drive is not the same model as the others.

Answer

The RAID controller is overheating.

Answer

The new drive is not properly seated in the bay.

Question 15

A customer reports that their new SSD is not detected by the BIOS. The drive is properly connected to the SATA port and power supply. What is the most likely cause of this issue?

Accepted Answer

The SSD needs to be initialized in Disk Management.. This question tests basic storage troubleshooting. The most common reason a new SSD is not detected is that it has not been initialized and formatted in the operating system. The BIOS detects the hardware, but the OS requires initialization to recognize the drive.

Answer

The SATA cable is faulty.

Answer

The power supply unit is insufficient.

Answer

The SSD is incompatible with the motherboard.

Question 16

A user complains that their external USB hard drive is making a clicking sound and is no longer recognized by any computer. What is the most likely cause?

Accepted Answer

The drive has experienced a mechanical failure.. Clicking sounds from a hard drive typically indicate a mechanical failure, such as a stuck read/write head or damaged platters. This is a classic sign of a failing drive, not a software or connection issue.

Answer

The USB cable is damaged.

Answer

The drive has suffered a logical failure.

Answer

The drive's enclosure is faulty.

Question 17

A user reports that their computer is running very slowly and they hear a repetitive clicking sound from the case. The technician checks the SMART status of the primary hard drive and sees a 'Reallocated Sectors Count' value that is critically high. What should the technician do next?

Accepted Answer

Back up all important data immediately.. A high reallocated sectors count indicates the drive is failing and likely to suffer data loss. The priority is to back up critical data immediately, then replace the drive. Continuing to use the drive risks permanent data loss.

Answer

Run a disk defragmentation to improve performance.

Answer

Replace the SATA cable and power connector.

Answer

Disable the paging file to reduce disk activity.

Question 18

A technician is troubleshooting a server that uses a hardware RAID controller with four SSDs in RAID 10. The server randomly freezes and the event log shows 'Lost communication with drive' errors. The drives pass SMART tests. What is the most likely cause?

Accepted Answer

The RAID controller firmware is corrupted.. Intermittent communication errors with drives that pass SMART tests often point to a faulty RAID controller, cable, or backplane. Since the drives themselves are healthy, the issue is likely with the controller or its connection to the drives.

Answer

The SSDs are experiencing write amplification.

Answer

The SSDs need to be defragmented.

Answer

The server's power supply is failing.

Question 19

A technician is building a workstation for video editing and needs to configure a RAID array for maximum performance without redundancy. The motherboard supports RAID 0, 1, 5, and 10. Which RAID level should the technician choose?

Accepted Answer

RAID 0. RAID 0 stripes data across multiple drives, offering the best read/write performance by utilizing all drives simultaneously. However, it provides no fault tolerance, meaning if one drive fails, all data is lost. This matches the requirement for maximum performance without redundancy.

Answer

RAID 1

Answer

RAID 5

Answer

RAID 10

Question 20

A company's file server uses a RAID 5 array with five 4 TB hard drives. One drive fails and is replaced. During the rebuild, the server crashes and the RAID controller reports that the array is 'Failed'. What is the most likely reason for this catastrophic failure?

Accepted Answer

A second drive failed during the rebuild process.. In RAID 5, a single drive failure is survivable, but during rebuild, the remaining drives are under heavy read stress. If another drive fails or has an unrecoverable read error, the array fails. This is known as a 'double fault' during rebuild, a common risk with large-capacity drives.

Answer

The new drive was not properly formatted before installation.

Answer

The RAID controller cache battery is dead.

Answer

The rebuild was attempted while the server was under heavy load.