What usually fails on a hard drive?

Mechanical Failures

Mechanical failures occur when the internal components of the hard drive no longer function as intended. Some common mechanical failures include:

Read/Write Heads: The read/write heads are responsible for reading and writing data on the platters. They float nanometers above the disk surface. If they fail, touch down on the platters, or become misaligned, data will become inaccessible.1

Platters: Platters are disks inside the hard drive that store data. If platters become physically damaged or warped, the drive may fail. Contaminants inside the drive can also cause scratches and corrosion on platters.2

Spindle Motor: The spindle motor rotates the platters at high speeds. If the motor seizes up or fails, the platters will stop spinning and data will become inaccessible.2

Logical Failures

Logical failures occur when there is no physical damage to the hard drive hardware, but data cannot be accessed from the drive due to corruption in the file system or other software issues. Some common causes of logical failure include:

File system corruption: The file system manages how data is stored on the hard drive. If it becomes corrupted, the drive may show up as raw space or be inaccessible even though the hardware is functioning. File system corruption can occur from sudden power loss, software issues, driver conflicts or other errors.

Bad sectors: All hard disks have some bad sectors — areas of the platter that are physically damaged. The drive firmware marks these sectors as bad so they are not used for data storage. However, if the number of bad sectors exceeds the spare sector threshold, data loss and inaccessibility can occur. Bad sectors often increase as a result of physical damage and old age.

Sources:
https://www.salvagedata.com/common-causes-of-hard-drive-failure/
https://en.wikipedia.org/wiki/Hard_disk_drive_failure

Firmware Failures

One common cause of hard drive failure is issues with the drive’s firmware. Firmware is the low-level software that controls the basic functions of the hard drive and allows it to communicate with the computer’s operating system. Problems with outdated, buggy, or corrupted firmware can lead to a variety of errors and failure modes.

Some signs of firmware issues include the drive not being recognized or showing up incorrectly in the BIOS, slow or erratic performance, failure to spin up or initialize, and more. Often, firmware bugs occur after a failed firmware update or flash. The firmware controls critical components like the motor controller, cache, and onboard processor. So firmware glitches can disable the drive’s basic functionality.

Troubleshooting firmware issues can be difficult for end users, often requiring advanced diagnostics tools. Updating to the latest firmware revision from the manufacturer is one solution. In severe cases, the drive may need firmware reprogramming from a specialized data recovery service. Preventative measures include avoiding unnecessary firmware updates and using manufacturer tools to flash firmware instead of third-party software.

Overall, firmware bugs account for a significant portion of hard drive failures. As firmware complexity increases to handle new technologies like SMR, proper firmware design and implementation remains crucial for reliability.

Power Failures

One of the most common causes of hard drive failure is a power outage or surge. When the power suddenly cuts out or spikes, it can damage the sensitive electronic components inside a hard drive.

Power surges and spikes send an overload of electricity to the drive, which can fry the circuits on the hard drive’s printed circuit board (PCB). This can render the drive completely dead and unresponsive. Even small power fluctuations can corrupt data on the drive by interrupting read/write processes before they are completed.

According to experts, power outages account for around 20% of all hard drive failures each year. Uninterruptible power supplies (UPS) can help protect against damage from power fluctuations, but they don’t always provide full protection from prolonged outages. Recovering data after a power-related failure often requires professional help.

“Power losses and electrical surges account for the overwhelming majority of our data recovery cases,” says Gillware, a leading hard drive recovery service. “Even momentary power interruptions can damage or corrupt file systems and render a drive inoperable.” [1]

Overheating

Overheating is one of the most common culprits of hard drive failure. If a hard drive overheats, it can start to degrade the drive’s components and performance. There are a few key reasons a hard drive may overheat:

Poor ventilation – Hard drives generate heat as they operate, and need sufficient airflow to keep cool. If they are in a tightly enclosed space without fans or ventilation, heat can build up quickly. Dust buildup inside a computer case can also block airflow and cause overheating. Proper ventilation, filtered intakes, and clean interiors are essential to prevent overheating (Source).

Failing fans – Many computer cases rely on cooling fans to maintain airflow. If these fans fail or spin more slowly due to age and wear, heat will not dissipate as effectively. Replacing old fans regularly can help avoid overheating issues.

Component Failure

One of the most common causes of hard drive failure is the breakdown of internal components. Hard drives contain many intricate parts that work together to read and write data, including the read/write heads, actuator arm, spindle motor, controller board, and firmware chip.

The spindle motor spins the platters inside the hard drive. If this motor fails, the platters will not be able to spin up to operating speed and the drive will not function properly. Spindle motors have a lifespan of around 60,000 hours in most consumer hard drives.

The actuator arm holds the read/write heads and allows them to move across the platters to access data. These arms can fail due to mechanical breakdowns or getting stuck. Dust, debris, wear and tear, and shock damage can all contribute to actuator arm failure over time.

Hard drive controller boards have chips and circuitry that control the various components inside the drive. Failures of controller board components like capacitors, ICs, and firmware chips can render a drive completely nonfunctional.

According to Backblaze stats, controller/electronics failures account for about 13% of annualized failure rates across the drives they use.

Manufacturing Defects

Despite quality control procedures, some flaws in hard drive production can slip through and lead to eventual failure. Manufacturers thoroughly test drives before shipping, but latent defects may not appear until months or years of use.

According to Backblaze’s drive stats for Q1 2023, manufacturing errors accounted for 8.1% of annualized failure rates across all drive models [1]. This represents a slight increase from 7.7% in 2022 and 7.5% in 2021 [2]. While not a leading cause of failure, manufacturing defects persist as an ongoing issue.

Common manufacturing flaws include faulty components, contamination, bad sectors, firmware bugs, integrated circuit issues, and problems with the drive heads or motors. Careful screening by manufacturers catches most defects, but some still escape into the market. Hard drives with undetected manufacturing issues tend to fail after 1-2 years of use.

To minimize failures from production defects, consumers should purchase drives from reputable brands, research model reliability, and avoid old or outdated stock.

Age and Wear

As hard drives age and accumulate usage hours, their failure rates tend to increase. According to Backblaze’s report on Q1 2023 drive stats, they observed an upward trend in the annualized failure rate (AFR) compared to previous quarters and the prior year.[1]

Backblaze reported an AFR of 1.54% in Q1 2023, up from 1.21% in Q4 2022 and 1.22% in Q1 2022. This illustrates the impact of aging on failure rates. In addition, Backblaze noted that AFRs start low when drives are new and steadily increase over time, with drives over 4 years old having much higher AFRs. For example, 8-10 TB drives over 4 years old had an AFR of 3.8% in Q1 2023.[1]

Furthermore, mean time between failures (MTBF) ratings also account for the effect of age on reliability. MTBF ratings are lowered to reflect average failure rates over the lifetime of a drive, rather than just when new.

Improper Use

One common cause of hard drive failure is improper physical handling that can damage the sensitive internal components. Hard drives contain rapidly spinning platters and magnetic read/write heads that float microscopically close to the platters. Any sudden jostling, dropping, or physical shocks can cause the heads to crash into the platters, scraping off the thin magnetic coating and destroying data. Only a slight tap against a hard surface while powered on can be enough to cause irreparable damage. Laptops are especially prone to drops and impacts during mobile use.

According to Salvagedata.com, dropping a powered-on laptop from 4-5 feet or higher frequently shatters storage drive components. Even a shorter drop onto a hard surface or jostling during transportation can ruin an HDD. Users should avoid moving a laptop while it’s powered on and handle devices gently. Additionally, operating hard drives in excessively vibrating environments may lead to premature failure over time as reader heads gradually degrade platters.

Preventative Measures

There are some practices you can follow to help prevent and protect against hard drive failure:

Using RAID (Redundant Array of Independent Disks) helps safeguard your data by distributing it across multiple drives. If one drive fails, your data remains intact on the other drives. There are different RAID configurations that provide different levels of redundancy and performance.

Regularly backing up your data is crucial – hard drive failures can happen unexpectedly at any time. Back up to an external drive or a cloud backup service. Make sure your backups are versioned so you can restore previous copies if needed. Test restoring from backups periodically to verify they work.

Be gentle with hard drives and avoid jostling or bumping them when powered on and spinning. Sudden movements can damage components. Also allow proper ventilation and cooling. High temperatures can accelerate wear and tear.

If possible, keep drives turned off when not in use to maximize lifespan. However, power cycling drives frequently can also cause issues, so balance downtime with convenience.

Use a surge protector, UPS (uninterruptible power supply), or battery backup for additional protection against power fluctuations that can harm drives.

Handle drives carefully by the edges and avoid touching sensitive components like connector pins. Static electricity can also damage electronics, so ground yourself before handling drives.

Keep drives away from magnets, liquids, dust, and smoke which can all be problematic. Store in a clean, dry, temperate environment.

Avoid using consumer drives in harsh environments or mission critical scenarios. Enterprise or NAS rated drives are engineered for longevity in heavy usage.

Maintain your hardware and OS by installing the latest updates, drivers, and firmware versions which often include drive improvements.

Lastly, ensure proper cable connections. Faulty or loose connectors can interrupt communication and cause damage over time.