External hard disks have become a popular way to expand storage and back up files. But how reliable are they? There are several factors that can affect the reliability of external hard drives.
What is an external hard disk?
An external hard disk is a portable storage device that can be attached to a computer via USB, Firewire, Thunderbolt, or wirelessly. It provides additional storage space and allows you to back up files for safekeeping.
External hard disks typically consist of a standard hard disk in a secure enclosure. The enclosure connects to the computer through an external interface like USB.
Why do people use external hard disks?
There are several key reasons people use external hard drives:
- Additional storage space: External hard drives provide a simple way to expand the storage capacity of your computer. If the internal hard drive is full or nearly full, an external drive can offer breathing room.
- Data backup: External hard drives make it easy to back up important files. This provides protection in case the internal drive crashes or data is lost.
- Data portability: External hard drives are small and lightweight, making them easy to transport files from one location to another.
- Privacy: External hard drives provide more security for sensitive files since they can be disconnected from the network and stored safely when not in use.
- File sharing: Files can easily be shared with others by using an external drive to transfer files from one computer to another.
Are external hard disks reliable for long-term data storage?
External hard disks can provide reliable storage for long-term data retention, but there are some caveats:
– The reliability depends on the quality of the drive and enclosure. Higher-end drives typically last longer.
– External hard drives are still mechanical devices with moving parts. This makes them more susceptible to failures and data loss compared to solid state drives.
– Portable external drives may be prone to damage from drops, impacts, liquids, dust, etc if not cared for properly. Desktop drives not subject to physical movement are less prone to these risks.
– Any drive can fail unexpectedly. So it’s essential to back up important data on an external drive to a second backup drive or other location.
So while external hard drives are reasonably reliable for long-term storage if proper precautions are taken, they are not infallible. Proper drive care and backup practices are essential.
Factors That Affect Reliability
Drive Quality
Higher quality external drives are often more reliable than cheaper low-end models. This is due to several factors:
- Brand name: Reputable manufacturers like Western Digital and Seagate generally produce drives with better reliability than lesser known brands.
- Build quality: More rugged housing and components improve lifespan and resistance to problems.
- Drive technology: Newer drive iterations usually offer better longevity and capabilities.
- Warranty: Longer warranties often correlate to more reliable units. Consumer-grade drives often have 1-2 year warranties while pricier enterprise models offer 3-5 years.
Cheap external hard drives may have higher failure rates. But even high-end drives can still fail unexpectedly. So data backup is still essential.
Drive Interface
The connection interface used by an external drive can impact reliability:
- USB: The most common interface. Easy to use but may lack capabilities of faster interfaces.
- FireWire: Not as common today. Fast performance but reaching end of life.
- Thunderbolt: Very fast interface but not universally supported.
- Ethernet: Reliable and fast but less convenient for individual use.
A robust physical connection is important to provide consistent connectivity. Connection problems can lead to data corruption or loss if drives are disconnected during use.
Drive Enclosure
The protective enclosure can affect external hard drive reliability:
- Plastic enclosures are lightweight but offer less protection from impact and drops.
- Aluminum enclosures dissipate heat better and cushion the drive if dropped.
- Rugged cases are bulkier but protect drive from water, dust and severe impacts.
- Fanless designs avoid failure points but may allow drive to run hotter.
A proper enclosure protects the drive inside from environmental threats that can damage components or cause data loss.
Physical Damage
Unlike internal hard drives, external drives are more prone to physical damage:
- Drops: Portable drives can be dropped, hit or impacted during movement, which can damage components.
- Dust and debris: External drives are more exposed to environmental contaminants that can enter the enclosure and interfere with operation.
- Liquid damage: Drinks, splashes or other liquids in proximity can infiltrate the enclosure and cause electrical shorts or corrosion.
Careful physical handling reduces the likelihood of external hard drive failure. Desktop drives not subject to movement are less susceptible to drops and impacts.
Power and Connections
Improperly disconnecting or inadequate power also factor into external hard drive reliability:
- Disconnecting during activity: Unplugging the drive while it is reading or writing data can cause corruption or drive errors.
- Insufficient power: Low-quality cables, ports, hubs or power supplies can provide unstable power to the drive.
- Cluttered connections: Nearby devices or cables can interfere with proper connections, power and air flow.
Following proper drive connection and disconnection procedures reduces electronic issues. High-quality cabling and connections ensure stable power delivery.
Failure Rate Statistics
While individual experiences can vary, studies have been done attempting to quantify overall failure rates among certain brands and models of external hard drives:
| Brand | Model | Annual Failure Rate |
|---|---|---|
| Western Digital | My Book | 3.9% |
| Western Digital | Elements | 6.8% |
| Seagate | Expansion | 4.2% |
| Toshiba | Canvio | 5.2% |
These studies found typical failure rates under 5% per year for many popular external hard drive models from leading brands like Western Digital and Seagate. However, there is still considerable variation based on individual usage habits and environmental conditions.
Some key pointers on failure rate statistics:
- Enterprise-class drives designed for businesses and servers often have lower failure rates around 2-3% per year.
- Failure rates tend to increase after 2-3 years as drives age, so newer models may fail less often.
- Failure rates are averages – individual drives may still fail well before or after the average.
- Environmental factors and physical handling can accelerate failures.
But overall, these studies reinforce that popular external hard drives deliver reasonably reliable longevity if used responsibly and backed up.
Best Practices for Reliability
While no external hard drive is 100% immune to failure, you can follow some best practices to increase reliability:
Choose a Reputable Brand
Stick with leading brands known for quality:
- Western Digital
- Seagate
- Toshiba
- LaCie
- Samsung
Avoid discount brands that may cut corners on quality. Check reviews to identify models with higher than average failure rates.
Select a Robust Enclosure
For portable external drives, select a design with durable casing that provides ample airflow and heat dissipation. Metal cases often outperform plastics. For desktop drives, nearly any enclosure will suffice since they are not moved.
Use Proper Connections
Always eject the external drive before disconnecting. Use shorter cables when possible, and high quality USB or Thunderbolt cables to minimize power and connection issues. Insert cables carefully to avoid damage to ports.
Carefully Handle Portable Drives
Avoid dropping drives and subjecting them to severe impact or vibration in transit. Carry them safely in padded bags or cases when travelling. Handle gently and avoid liquid exposure.
Manage Drive Heat
Allow adequate ventilation around drives to prevent overheating. Do not enclose portable drives in other objects while powered on. Leave desktop drives powered on in an open, ventilated area.
Backup Your Data
No single drive is 100% reliable. Always maintain an additional copy of important data either on a second external drive or in the cloud. That way a single drive failure does not lead to data loss.
Following these best practices will maximize the reliability and lifespan of your external hard drive. But also expect that drives have a limited lifespan of around 3-5 years under typical use before considering replacement.
External SSD vs HDD Reliability
External solid state drives (SSD) using flash memory represent an increasingly popular alternative to traditional rotational hard disk drives (HDD).
Comparing SSDs and HDDs:
| Characteristic | SSD | HDD |
|---|---|---|
| Reliability | Fewer moving parts, more shock resistant | Contains fragile moving magnetic platters |
| Durability | Withstands vibration, drops, impacts | Prone to damage from bumps and drops |
| Speed | Much faster data access and transfer speeds | Slower speeds due to mechanical operation |
| Noise | Silent operation | Detectable hum or whirring |
| Heat | Cool, no moving parts | Moving parts produce more heat |
| Power | Lower power consumption | Higher power draw, requires spinning up |
The simpler construction and lack of moving parts gives external SSDs and advantage for reliability and durability over traditional external hard disk drives. However, HDDs currently remain much cheaper per GB of storage. So each still have appropriate uses.
External RAID Reliability
Using multiple external hard drives together in a RAID array can increase redundancy and reliability.
What is RAID?
RAID stands for Redundant Array of Independent Drives. It allows multiple hard drives to be grouped together for performance, capacity or redundancy.
There are different RAID levels with specific configurations:
- RAID 0 – Two or more disks in a striped set, increases speed but no redundancy
- RAID 1 – Disk mirroring over two drives for full redundancy
- RAID 5 – Striping with distributed parity for speed and redundancy
- RAID 10 – Striping over mirrored subsets of drives
Benefits of External RAID
Key advantages of using external RAID arrays include:
- Increased storage capacity – Combine multiple drives into a single large volume.
- Faster access speeds – Read/write to multiple drives to increase performance.
- Failover redundancy – If one drive fails, others retain the data.
- Flexibility – Add more drives to expand capacity.
Implementing External RAID
Setting up an external RAID array requires:
- External hard drives – Use identical models for simplicity.
- RAID enclosure – Provides necessary connections and RAID controller.
- RAID software – Manages the RAID array.
Popular interfaces for external RAID arrays include USB, Thunderbolt and eSATA for connecting to computers.
RAID Improves Reliability
The redundancy of RAID configurations like levels 1 and 5 helps mitigate and recover from individual drive failures. If one drive fails, data integrity is retained. The failed drive can then be replaced and rebuilt in the RAID array.
However, poor quality drives, multiple simultaneous failures, or controller failures can still lead to array and data loss. So external RAID alone should not be relied on for backup. Critical data should be backed up outside the array.
Conclusion
External hard drives provide convenient expanded storage and backup capabilities. While no drive lasts forever or is completely immune to failure, external hard drives are generally quite reliable if treated properly. Leading drive brands like Western Digital and Seagate deliver average annual failure rates around 3-5%, with higher quality models approaching just 2-3% yearly failure rates.
Practices like proper physical handling, drive care, using quality components, and avoiding unexpected disconnects can dramatically improve the lifespan of an external drive. Sticking to reputable brands, frequently backing up data, monitoring drive health, and being prepared to replace drives as they age will result in excellent long-term experiences with external storage solutions.