When it comes to choosing storage solutions for backing up important files and data, two of the most common options are traditional hard disk drives (HDDs) and solid state drives (SSDs). Both have their own sets of pros and cons when used for backup purposes. In this comprehensive guide, we will compare HDDs and SSDs across a number of factors to help you determine which is the better backup storage device for your needs.
Cost per GB
One of the most basic considerations when choosing a backup drive is cost per gigabyte of storage. HDDs currently offer a much lower cost per GB compared to SSDs. For example, a 4TB HDD costs around $100 while a 4TB SDD costs around $500. This means HDDs allow you to maximize storage capacity and backups within a given budget. The tradeoff is that SSDs provide much faster read/write speeds. But for backups where storage space is a priority and speed is less important, HDDs provide unbeatable value.
Durability and Longevity
When it comes to durability and longevity, SSDs tend to outlast HDDs for a few key reasons. First, SSDs have no moving parts whereas HDDs use a spinning platter and movable read/write head to access data. This makes HDDs more susceptible to damage from drops, vibration, magnetism, etc. Second, SSDs can withstand more extreme temperatures which is useful if storing backups in uncontrolled environments. Finally, SSDs have higher tolerance for shock, can withstand more rewrite cycles, and generally last longer than HDDs when used appropriately. So if longevity is critical, SSDs may justify their higher cost.
Transfer Speed
SSDs provide tremendously faster read/write speeds compared to HDDs. This is because SSDs access data electronically with no moving parts while HDDs rely on physical platter rotation and head movement. For example, HDDs max out around 160MB/s transfer speed for both reads and writes. In comparison, SATA SSDs offer 550MB/s reads and up to 520MB/s writes. NVMe SSDs are even faster with over 3500MB/s sequential reads and 3000MB/s writes. This makes SSDs ideal for tasks like system imaging where fast transfer speeds can significantly reduce downtime when backing up large amounts of data.
Capacity
When it comes to storage capacity, HDDs are the clear winner. Today’s HDDs max out around 20TB for consumer models and up to 100TB for enterprise servers. In comparison, consumer SSDs range from 500GB up to around 8TB for top of the line models. For highly capacity intensive backup needs like backing up media servers or data archives, HDDs provide unbeatably dense storage at the lowest cost. The tradeoff is slower transfer speeds which may be less critical for backups that aren’t accessed frequently after the initial write.
Fragmentation
One advantage of SSDs is that they generally do not suffer from fragmentation issues. Fragmentation happens when files are written to different parts of the disk which reduces read/write performance. Defragmenting the drive helps optimize the layout of files but this process is relatively slow for HDDs. SSDs, on the other hand, do not require defragmenting at all thanks to their fast electronic data access. This provides more consistent performance over time as the backup drive fills up.
Failure Rate
When it comes to likelihood of failure, SSDs tend to be more reliable than HDDs. Being electronic with no moving parts reduces the ways an SSD can fail. They are not susceptible to mechanical failures related to the drive motor, head crash, or RPM. SSDs are also more shock and vibration resistant. However, HDDs still have fairly low annual failure rates around 2-3% depending on quality and usage patterns. So while SSDs have the reliability advantage, HDD failure rates are still fairly low for drives used appropriately.
Availability
Both HDDs and SSDs are readily available from electronics retailers online and in stores. However, there is significantly more variety and selection for HDDs compared to SSDs when it comes to factors like form factors, interfaces, capacities, and price points. HDDs are a mature technology with many manufacturers producing models catering to both consumer and enterprise needs. The SSD market is also expanding quickly but HDDs still have the edge when it comes to broad availability and overall options.
Power Consumption
SSDs use less power and run cooler than HDDs which can help reduce energy costs for backup storage. HDDs need to spin up the platter which takes more power compared to SSDs accessing data electronically. For example, a typical 3.5″ 7200 RPM HDD uses around 6-9 watts in operation compared to just 2-3 watts for a 2.5″ SSD. This also results in less heat generation helping SSDs run cooler. Reduced power use and lower temperatures provide additional benefits like longer component lifespan and lower cooling requirements.
Noise Level
With no moving parts, SSDs run virtually silent generating zero noise pollution. HDDs produce audible noise during operation due to the spinning platter and moving read/write arm. While not overly distracting, this humming sound can be undesirable in quiet home or office environments. SSDs avoid this issue entirely operating silently and making them better suited around people. Some server-focused HDDs even come with noise reduction features like sound-dampening casings to minimize disturbance.
Encryption
Both HDDs and SSDs support data encryption to protect backups from unauthorized access. HDDs offer hardware-based encryption supporting the Advanced Encryption Standard (AES). SSDs also support AES hardware encryption to securely encode data without performance overhead. This ensures even if the backup drive is lost or stolen, the data remains inaccessible without the encryption key. With support for AES-256 and other standards, both HDDs and SSDs provide robust encryption suitable for securely storing backups.
Compatibility
In terms of compatibility, HDDs and SSDs support connection via all common interfaces like USB, SATA, and PCIe. This broad interface support ensures either can be used as backup storage in nearly any desktop or server. Most modern operating systems also support using both HDDs and SSDs interchangeably. However, some older systems had limited SSD support so HDDs are the safer choice for wider backwards compatibility. But for modern systems, HDDs and SSDs are generally interchangeable in terms of interface and OS support.
File System Support
HDDs and SDDs are both compatible with modern file systems like NTFS, exFAT, and EXT4 for storing backup data. However, some differences exist when it comes to performance optimizations and ideal use cases. For example, NTFS provides features tailored towards HDDs like fragmentation reduction. EXFAT and EXT4 work well on SSDs with optimizations like wear leveling and filesystem journaling. So while both drive types are flexible in terms of file system support, optimizations can help match HDDs and SSDs to the file system that suits their strengths.
Backup Software Support
Leading backup software solutions support using both HDDs and SSDs as destination drives. Products like Acronis, Veeam, and StorageCraft all allow writing backup images to either HDD or SSD storage. Features like backup scheduling, compression, and backup types are also fully functional across HDD and SSD devices. So you can use your preferred software to back up critical data to either drive type based on your performance, capacity, and budget needs.
Recovery Time
When it comes to recovery time, SSDs provide a major advantage thanks to their much faster data access speeds. Recovering a 1TB system backup could take 1-2 hours from an HDD but less than 10 minutes from an SDD. This allows dramatically reducing downtime when restoring backups after data loss or system failure. Faster recovery gives businesses improved resilience and workers increased productivity. So for mission critical backup needs, SSDs are highly recommended over HDDs.
Backup Window
The backup window refers to the duration required to successfully complete a backup job. HDDs typically require a longer backup window due to their slower transfer speeds. Backing up 1TB to an HDD may take 3-4 hours depending on interface and drive speed. The same amount of data may backup in under an hour to an SSD. Shorter backup windows helps IT teams complete backups within defined maintenance windows. Incremental backups also run faster helping ensure backups stay up to date. For these reasons, SSDs are preferred when aiming to minimize backup windows.
Capacity Usage Efficiency
HDDs tend to provide more efficient usage of their available storage capacity compared to SSDs. This is because SSDs use some of their raw capacity to support wear leveling, garbage collection, RAID redundancy, and other background processes. For example, a 1TB SSD may only provide usable space of 931GB after accounting for system overhead. In comparison, HDDs dedicate nearly all their raw capacity to user storage. So those needing to maximize every last gigabyte may find HDDs provide slightly more cost-effective capacity.
Boot Backup Support
SSDs and HDDs both support backups for bare metal restore or OS reinstallation. With system image backups, either drive type can store a full bootable copy of the operating system. This provides the option to quickly restore to dissimilar hardware in the event of a fatal system failure. The key advantage of SSDs for boot backups is their faster transfer speed reducing downtime when recovering an entire system image. So SSDs work very well for boot backups thanks to their fast read performance.
Drive Wear
HDDs and SSDs handle drive wear differently. HDDs are susceptible to damage of the physical platter and read/write heads which can increase the likelihood of failure over time with use. SSDs wear down by using up their write endurance which is measured in terabytes written (TBW). However, modern SSDs last for many years even under heavy workloads. For backups that involve mainly writing with little rewriting, HDDs and SSDs both handle wear well. But SSDs are recommended for redundancy like RAID configurations which require more frequent writing.
Radiation Tolerance
HDDs are more susceptible to data corruption when exposed to radiation compared to SSDs. Radiation can flip data bits on HDD platters while SSD data is stored in radiation-hardened flash memory chips. This makes SSDs a safer choice for deployments in settings prone to greater radiation exposure like space, high altitude, or defence. For typical ground-level civilian settings, radiation is less of a concern so both HDDs and SSDs provide adequate data integrity.
Shock & Vibration Tolerance
SSDs are far more tolerant of shock and vibration compared to HDDs. Dropping an HDD can cause catastrophic head crashes or motor failure. SSDs are resistant to shock with no risk of mechanical failure. Vibration can also disrupt HDD head positioning reducing performance. SSDs are unaffected by vibration during data access. For backup in rugged environments with shock or vibration risks, SSDs are by far the safer choice over HDD mechanical weaknesses.
Formatting
Both HDDs and SSDs can be quickly formatted using tools built into major operating systems like Windows Disk Management, macOS Disk Utility, and Linux GParted. These tools allow erasing and repartitioning a drive to prepare it for data backups. SSDs support both standard formatting or more optimized techniques like secure erase. This quickly wipes all residual data and restores peak write performance helpful when recycling SSDs between users. So HDDs and SSDs give IT teams flexible drive formatting options.
Data Integrity
Maintaining data integrity is critical for useful backups. HDDs ensure integrity through CRC checksums for error detection. SSDs leverage ECC memory and internal data path protection to detect and correct a higher number of potential errors. Overall, SSDs achieve better data integrity than HDDs which still provide adequate protection for most use cases. For archival data that must be perfectly preserved for decades, SSDs provide that extra level of integrity assurance.
Drive Operations
From an IT administration perspective, SSDs require less management and active monitoring compared to HDDs. HDDs are mechanical devices with more components that can degrade over time. Tools like S.M.A.R.T. monitoring help track HDD health metrics like reallocated sectors and temperature. SSDs have minimal moving parts and consistent performance avoids this need for in-depth monitoring. This allows IT teams to worry less about backup drive maintenance when using SSDs.
Environmental Factors
SSDs are better suited for operation under more extreme or unfavorable environmental conditions compared to HDDs. For example, HDDs cannot withstand high altitudes or sub-zero temperatures which can cause mechanical failure. SSDs operate reliably in these scenarios thanks to their resilience and lack of moving parts. Similarly, SSDs are rated for higher maximum operating temperatures up to 70°C. So for deployments requiring environmental hardiness, SSDs easily outclass HDD limitations.
Portability
For portable backup storage, SSDs have a major advantage thanks to their compact, lightweight, and rugged design. HDDs contain sensitive platters and heads that are easily damaged by drops or vibration. SSDs contain no moving parts and resist damage in transit. This makes them ideal for backups that need to be frequently moved between locations. With high capacity portable SSDs now widely available, they eliminate the fragility issues around transporting HDD backups offsite.
Upgradeability
One advantage of HDDs is that their storage capacity can be easily expanded with enclosure upgrades. For example, replacing a 2 bay NAS with a 5 bay model allows adding more HDDs for increased backup storage. Currently, expanding SSD capacity is not as simple since capacities max out around 8TB. But as SSD capacities continue improving, their upgradeability will also increase for backup needs. For now, those needing easy storage expansions are still better served by HDDs.
Security
Backup drives require security against both physical theft and data theft. HDDs are more susceptible to physical damage like head crashes if devices are dropped or impacted. SSDs are far more physically resilient with no risk of mechanical failure when handled roughly. Both HDDs and SSDs support encryption to protect against data theft. But SSDs face lower risks of somebody recovering magnetic data remnants if a discarded drive is obtained. Overall, SSDs provide better security for backups thanks to physical and data protection.
Summary
In summary, SSDs provide major advantages for backups when it comes to:
- Transfer speed
- Recovery time
- Backup windows
- Durability and longevity
- Failure rates
- Noise levels
- Power efficiency
- Physical resilience
- Environmental hardiness
HDDs currently maintain advantages related to:
- Lower cost per gigabyte
- Higher maximum capacities
- Capacity utilization efficiency
- Upgradeability
- Broad availability
For most users, SSDs provide the best combination of speed, durability, and reliability for backup storage. The higher cost per gigabyte is mitigated by dropping SSD prices. And with speed being critical for both backup and recovery scenarios, SSDs easily justify their premium pricing in most cases.
Conclusion
When choosing between HDDs and SSDs for backup storage, SSDs are the clear winner in the majority of situations. The extra upfront cost is easily justified by their major advantages in transfer speed, resilience, environmental tolerance, and overall reliability. While HDDs maintain some benefits like larger capacities and lower cost per gigabyte, these factors are less critical for backups that prioritize speed and integrity.
For home users and SMBs needing simple, fast, and rugged backup solutions, external SSDs are highly recommended over HDDs. Enterprise and specialty use cases like archival may still benefit from HDD density and cost efficiencies. But SSDs continue closing these gaps rapidly. Thanks to their technical advantages and steadily improving value, SSDs are becoming the top choice for both consumer and business backup needs moving forward.