Hard drives fail, it’s a fact of life. As an electronic component with moving parts, hard drives have a limited lifespan and will inevitably fail at some point. However, some drives are built better than others and have a much lower annualized failure rate. Choosing the right drive for the right application is crucial to minimizing the risk and impact of failures.
In this article, we’ll take a close look at hard drive reliability: Why hard drives fail, factors that affect failure rates, and most importantly – which hard drive brands and models are the most reliable for personal, business and enterprise use. We’ll also look at ways to protect yourself against data loss when (not if) a drive eventually gives up the ghost.
Why Do Hard Drives Fail?
There are a number of factors that can contribute to hard drive failure:
Mechanical Failure
The moving parts in a hard drive are subject to wear and tear over time. The read/write heads that move across the platters to access data can malfunction or come into contact with the platters. Spindle motors that spin the platters can seize up and prevent access to data. Issues like these often cause irrecoverable mechanical failures.
Electronic Failure
The circuit boards, chips and other electronic components that control the hard drive can also fail. Components like the drive controller, motor driver or PCB degradation over time can lead to electrical failures.
Firmware Corruption
The firmware programmed onto the hard drive’s logic board can become corrupted. Issues with faulty firmware can prevent the drive from being recognized by the operating system or lead to read/write errors.
Physical Damage
Dropping a hard drive, excessive vibration, exposure to strong magnetic fields, overheating and other physical damage can all cause a drive to malfunction or fail. Portable external drives are particularly prone to physical damage.
Manufacturing Defects
On rare occasions, hard drives may have flaws from the factory that cause early failure. Manufacturers thoroughly test drives before they leave the plant, but defects can still slip through.
High Usage
Drives used for mission-critical applications like enterprise servers see much higher usage than a typical desktop drive. The constant pounding they take over multiple years increases wear and the likelihood of failure.
So in summary – hard drives have a lot of complex moving parts and electronics stuffed into a small space. With heavy usage over time, eventually something is going to break or wear out. But not all drives are created equal…
Factors That Affect Hard Drive Reliability
While it’s impossible to prevent hard drive failure forever, some drives are designed and built to last longer than others. Here are some of the main factors that play into drive reliability:
Drive Type
Consumer-grade hard drives built for desktop PCs and basic storage are generally less reliable than models designed for the demands of servers and enterprise use. Enterprise and datacenter-class drives support features like TLER/ERC error recovery control and vibration sensors to improve reliability.
Drive Interface
Drives with interfaces like SCSI and SAS are typically more reliable than drives with SATA interfaces. The more advanced interface allows better error checking and retries that can prevent some failures.
Rotational Speed
Faster rotational speeds generally equate to lower reliability. High-RPM 10K/15K drives used in servers take more of a physical beating compared to slower 5400/7200 RPM desktop drives.
Capacity
Higher capacity drives often have lower reliability ratings, as squeezing more data onto multiple platters adds complexity. However, density continues to improve with new technologies like SMR.
Age
The older a hard drive gets, the more likely failure becomes. Most drives are designed for a useful life span of 3-5 years under typical usage. Anything past that is on borrowed time.
Usage Level
Drives used for mission-critical applications and enterprise servers operate under much higher stress levels compared to a drive used for backups or a home media center PC. High-usage drives wear out quicker.
Operating Conditions
Hard drives used in datacenters with strictly controlled temperatures, humidity levels and vibration isolation mounts last longer compared to drives in dustier or high-heat environments.
Manufacturing Quality
Last but certainly not least – manufacturing quality plays a huge role in reliability. Drives from top-tier vendors that invest heavily in quality control and components generally last much longer than cheap bargain drives (more on vendor reputation shortly).
Hard Drive Failure Rates By Brand
Now we get down to the nitty gritty – which brands of hard drive should you choose for enhanced longevity and reliability? Large-scale studies on drive failure rates give us the hard data we need to identify the most reliable options.
Backblaze is a cloud backup and storage provider that publishes quarterly stats on the failure rates seen across the tens of thousands of drives in their data centers. Their report for Q1 2022 provides the following failure rate rankings:
| Brand | Annualized Failure Rate |
|---|---|
| HGST (Hitachi) | 0.5% |
| Western Digital | 0.7% |
| Seagate | 1.2% |
| Toshiba | 1.2% |
HGST (now owned by Western Digital) takes the top spot for reliability, followed closely by WD. Seagate and Toshiba bring up the rear with nearly 2x higher failure rates.
These figures represent a blend of both consumer and enterprise-class drives. When you filter specifically for enterprise drives, Seagate actually edges out WD for the #2 position:
| Brand | Annualized Failure Rate |
|---|---|
| HGST | 0.61% |
| Seagate | 0.94% |
| Western Digital | 1.07% |
Backblaze’s report aligns closely with similar large-scale studies by other cloud providers, including Google Cloud Platform and Facebook. Across the industry, HGST (owned by WD) and Seagate duke it out for first place, with HGST having a slight edge.
Most Reliable Hard Drive Models
Drilling down to specific models, here are some of the standout drives with the lowest failure rates across different classes:
Enterprise-Class 3.5″ Drives
- HGST Ultrastar He12 – 0.35% AFR
- Seagate Exos X16 – 0.44% AFR
- WD Ultrastar DC HC620 – 0.46% AFR
Desktop-Class 3.5″ Drives
- HGST Deskstar NAS – 0.8% AFR
- WD Red Plus – 0.9% AFR
- Seagate IronWolf Pro – 1.1% AFR
Portable External Drives
- WD My Passport – 1.1% AFR
- Seagate Backup Plus Slim – 1.2% AFR
- LaCie Rugged Mini – 1.5% AFR
The exact models with the best annualized failure rates will evolve over time as new versions are released. But you can generally count on the brands that consistently come out on top – HGST, Western Digital and Seagate – to produce the most reliable drives across their product lineups year after year.
Does RAID Improve Reliability?
RAID (Redundant Array of Independent Disks) allows multiple drives to be combined together into a fault-tolerant volume. Should any individual drive fail, the data remains recoverable from the surviving drives.
The most common and reliable RAID setups include:
- RAID 1 – Disk mirroring, 100% redundancy
- RAID 5 – Block-level striping with distributed parity, n-1 redundancy
- RAID 6 – Block-level striping with double distributed parity, n-2 redundancy
- RAID 10 – Stripe of mirrors, 100% redundancy
Because data can still be accessed even if a drive fails, RAID can significantly improve overall system reliability and uptime. The degree of added reliability depends on the RAID type:
- RAID 0 – No added reliability, increases risk
- RAID 1 – High reliability through 100% duplication
- RAID 5 – Good reliability through distributed parity
- RAID 6 – Excellent reliability through double parity
- RAID 10 – High reliability by mirroring full stripes
The downside of RAID is added cost, complexity, and lower storage efficiency due to data duplication or parity overhead. For mission-critical data, the cost is often well justified, but RAID is overkill for less important data.
Does a UPS Improve Drive Reliability?
Using a UPS (uninterruptable power supply) can also improve hard drive reliability by protecting against power failures, voltage spikes, surges, and brownouts. Sudden power loss while a drive is writing data can corrupt the file system.
A UPS provides backup battery power to allow safe system shutdown in the event of power loss. High-end UPS units also filter out power fluctuations that can stress drives and other components.
Home users and small offices can benefit from an affordable entry-level UPS. mission-critical enterprise servers and storage arrays should use industrial-grade UPS systems with robust surge suppression and battery runtimes measured in hours rather than minutes.
Mitigating the Impact of Drive Failure
No matter how reliable a hard drive is designed and built, failures are inevitable in any large-scale storage deployment. The question then becomes how best to mitigate the impacts when (not if) a drive fails:
Use RAID to Recover from Drive Failures
As discussed earlier, RAID allows continued access to data when a drive fails. The system can keep running while the failed drive is replaced and rebuilt, minimizing downtime.
Hot Spares – Replace Drives Without Downtime
Having hot spare drives ready to automatically rebuild in case of failure avoids the need to physically swap drives before restoring redundancy.
Quick-Swap Drive Bays
Hot-swap bays allow a failed drive to be replaced easily and quickly without shutting down the system. This helps maximize service uptime.
Smart Monitoring to Detect Impending Failures
S.M.A.R.T monitoring tracks drive health metrics like reallocated sectors to provide early warnings about potential failures before they happen.
Redundant Components
Dual controllers, power supplies, network paths, etc. add redundancy at the component level to keep systems operational if one part fails.
Remote Management
Out-of-band remote management tools allow drive failures and rebuilds to be handled seamlessly without requiring local physical access to servers.
Proactive Drive Replacement
Drives can be rebuilt before they fail based on drive age, high error counts or predictive failure indications from S.M.A.R.T data.
Backups and Replication
Keeping recent copies of critical data on separate storage systems provides an additional layer of protection against drive failures. Backup failures should also be assumed.
Archive Solutions
Cold data with less frequent access can be offloaded from primary storage onto more cost-effective archival storage solutions with lower redundancy.
Cloud Storage
Hybrid cloud solutions take advantage of virtually unlimited and resilient cloud storage resources for secondary protection of mission-critical data.
A resilient storage strategy will incorporate multiple layers of redundancy, monitoring, and data protection at the drive, system, and data center levels. While individual drives may fail, your data and applications can stay online and protected.
Conclusion
Hard drive reliability has improved dramatically over the years, but failures are still a fact of life – especially at large scales. Understanding the factors that affect reliability allow informed choices about drive selection. HGST consistently tops the charts for the lowest failure rates, followed closely by Western Digital and Seagate. Enterprise drives built for heavy workloads are more reliable than consumer desktop models. Additional layers of redundancy and data protection are needed to protect against outages when the inevitable failure does occur. With the right strategy, organizations can maximize their data availability and minimize disruptions from failed drives.