Flash storage, also known as solid state drives (SSDs), offer faster read and write speeds, better durability, and lower power consumption compared to traditional hard disk drives (HDDs). However, flash storage has a limited lifespan and will eventually wear out after a certain number of write/erase cycles. So how long can you expect flash storage to last?
What determines the lifespan of flash storage?
There are several key factors that determine how long flash storage will last:
- Total bytes written – The total amount of data written to the drive over its lifetime. The more data written, the faster it will wear out.
- Write amplification – Due to the way SSDs handle writes, the actual amount of data written can be higher than what the host system requested due to garbage collection and wear leveling. This write amplification reduces endurance.
- Capacity – Higher capacity SSDs tend to last longer because the writes are distributed over more flash memory chips.
- NAND type – Single-level cell (SLC) NAND flash lasts longer than multi-level cell (MLC). MLC tends to be used in consumer SSDs while SLC is used in enterprise drives.
- Wear leveling algorithm – The firmware algorithm that distributes writes across the drive to avoid wearing out one block of memory prematurely.
- Operating conditions – Factors like temperature can affect the lifespan of the drive.
Typical lifespan estimates
Most consumer SSDs today use MLC NAND flash and are rated for about 3,000-5,000 program/erase cycles. However, drive manufacturers usually provide a higher endurance rating based on the expected average workload over the warranty period, which is typically 3-5 years.
Here are some general lifespan estimates for today’s consumer SSDs:
- 250GB SSD: 75TB – 150TB of total bytes written
- 500GB SSD: 150TB – 300TB of total bytes written
- 1TB SSD: 300TB – 600TB of total bytes written
So for typical consumer usage, most SSDs will last at least 5 years before reaching the write endurance limit. Heavy workloads like video editing that write a lot more data will reduce the lifespan.
Factors that can reduce SSD lifespan
There are several usage scenarios that can significantly reduce the lifespan of an SSD:
- No wear leveling – If the drive is mostly filled with static data with little writing, the same cells may be programmed and erased repeatedly in a short span which can quickly wear them out.
- Excessive drive writes – Applications like video editing, virtual machines, databases etc can write tens of GBs per day, drastically reducing SSD lifespan.
- Excessively full drive – A filled up drive will require a lot more write amplification to reclaim space, reducing endurance.
- High temperature – Heat accelerates the breakdown of NAND flash cells.
Improving flash storage lifespan
Here are some tips to extend the lifespan of your SSD:
- Leave ample free space, at least 20% if possible, so the drive can wear level efficiently.
- Enable TRIM on your OS and run it periodically to notify the SSD of deleted data.
- Use a cooler system environment and consider a drive with better heat dissipation.
- For frequently overwritten data, use a RAM disk rather than storing it directly on SSD.
- Avoid unnecessary excessive writes from programs and features like search indexing.
Detecting SSD wear out
SSD controllers track something called host writes per day or drive writes per day to estimate the remaining endurance. Most SSDs today use the SMART attribute 231 to report this used endurance, which tools like CrystalDiskInfo can read.
When the remaining endurance drops below 10%, you should start thinking about drive replacement. The SSD will go into a read-only mode when it exceeds the device endurance limit.
Reallocated sector count (attribute 5) will steadily increase as the drive starts remapping bad flash blocks. A high count indicates the drive is nearing its end of life.
In addition, heavily worn out SSDs will have visibly slower write speeds and higher latency as it takes longer to find clean blocks for writing data.
SSD failure modes
An SSD typically fails due to one or both of the following modes:
- Write endurance expiry – The flash memory has exceeded its rated program/erase cycles meaning it can no longer reliably store data.
- Uncorrectable bit errors – The error correction code is unable to recover from errors caused by excessive flash cell leakage.
The latter failure mode can manifest even before reaching the advertised write endurance limit since bit errors accumulate gradually. Wear leveling and bad block management helps minimize such errors during the usable lifespan.
Data recovery from worn out SSDs
Once an SSD has exceeded its write endurance, data recovery becomes challenging:
- There is no mechanical component to attempt a physical recovery from.
- Advanced data recovery techniques like chip-off are expensive and have low success rates.
Your best bet is to ensure frequent backups of important data so it can be restored onto a new replacement drive. For enterprise use cases, vendors offer advanced SSDs with much higher endurance ratings.
If the SSD has suffered an unexpected failure before its rated endurance limit, there is a slightly better chance for data recovery through professional services.
Extending lifespan through over-provisioning
SSD controllers reserve some capacity for internal processes like garbage collection. This extra space is called over-provisioning and is typically 7% on consumer drives. This space improves performance and extends endurance.
On some SSDs, you can manually increase over-provisioning by leaving unpartitioned space. For example, leaving a 512GB drive with only 450GB partitioned can improve its lifespan.
However, theimpact on endurance diminishes beyond a certain level of over-provisioning. Leaving 20-30% free space is a reasonable target for improved endurance.
Do SSDs wear out from age alone?
No, SSD age by itself does not cause wear out or failure. NAND flash cells can retain data for up to 10 years without power. As long as the total bytes written is within rated endurance and bit errors are correctable, the SSD can continue functioning normally.
That said, aging can lead to issues like:
- Difficulty powering up after leaving unpowered for months.
- Increased bit errors as cells leak over time.
- Component failure like capacitors leading to potential data loss.
So while age alone doesn’t cause wear out, an older SSD is more likely to develop other issues compared to a newer one. Periodically powering on old SSDs can help avoid startup issues.
Do SLC SSDs last longer than MLC?
Yes, SLC or single-level cell SSDs offer substantially higher endurance compared to consumer MLC drives. A SLC flash cell stores just one bit, minimizing inter-cell interference that contributes to wear.
MLC tries to pack more storage density by storing 2 bits per cell. The narrow voltage margins lead to faster breakdown over repeated writes. Here is a comparison of endurance cycles for SLC vs MLC:
| Flash type | Endurance (P/E cycles) |
| SLC | 100,000 |
| MLC | 3,000 – 10,000 |
The downside is that SLC has much lower storage density and is more expensive. So SLC drives aretypically used in enterprise environments where longevity is critical.
Do PCIe/NVMe SSDs last longer than SATA SSDs?
The interface by itself does not affect SSD endurance in a meaningful way. Both SATA and PCIe NVMe drives use the same NAND flash chips.
However, NVMe drives tend to optimize more for performance. Many consume more power and run hotter which can potentially impact longevity. Enterprise NVMe SSDs designed for mixed workloads offer comparable endurance to enterprise SATA SSDs.
For typical consumer workloads, you can expect similar lifespan between SATA and PCIe NVMe drives of the same capacity from the same manufacturer.
How does RAID affect SSD lifespan?
Using RAID with SSDs introduces some tradeoffs in endurance:
- RAID 0 – Lifespan is shortened since total writes are spread over fewer drives. But higher performance reduces write amplification.
- RAID 1 – Lifespan stays similar to a single drive as writes have to go to both drives.
- RAID 5 – Parity writes cut into some of the endurance. But localized writes are reduced.
- RAID 10 – Similar to RAID 1 as all writes go to two drives. Read performance improves.
In general, RAID improves SSD performance but at the cost of some endurance. The impact varies based on the RAID type. Assess your workload characteristics and rate of writes before choosing a RAID for SSDs.
Do SSDs stop working completely after wear out?
An SSD will go into a read-only mode after it exceeds the rated program-erase cycles. But many drives will still be partly usable in this mode.
Essential functions like mapping out bad cells, wear leveling and background garbage collection will no longer work. But data in healthy cells that are not worn out can still be read.
This allows recovering data copies or backups from a worn out SSD in read-only mode. But such SSDs are unfit for further general-purpose usage.
Conclusion
SSD lifespan is determined largely by the total data written over time. With moderate usage, most consumer drives last 5 years or more before exceeding endurance limits. Enterprise SSDs are rated for much higher endurance of 1-10 drive writes per day.
Wear leveling, TRIM, over-provisioning and minimizing unnecessary writes can help extend lifespan. Ensure you have backups of important data as worn-out SSDs have low recovery success.