How long does an SSD drive last? How to determine the approximate lifespan of an SSD drive

Replacing an old one on your computer HDD new SSD, few people will want to return to using regular hard drive. This reluctance is dictated mainly an undeniable advantage SSD before HDD in the speed of data access, but at the same time, many remain in the grip of doubts and fears regarding the durability of solid-state drives. As you know, everything SDD have a limited number of rewrite cycles.

And this often encourages users to use all means, sometimes completely unnecessary and even harmful, to minimize recording to disk.

In reality SSD-disks are not at all as short-lived as it might seem at first glance, and even those that are considered least reliable can withstand truly enormous volumes of recorded data. However, to know the approximate lifespan of your SDD won't hurt. It is not difficult to approximately determine the service life of a disk; the main thing is to know, at a minimum, its TBW (maximum volume that can be recorded) and the amount of data that has already been written and is expected to be written to disk within the nth amount of time. Approximate lifespan SSD can also be determined by knowing the number of rewrite cycles declared by the manufacturer.

What are SLC, MLC, TLC and TBW

Most solid state drives on the market are based on NAND, which in turn can use three types of memory chips: SLC , MLC And TLC .

The fastest and longest-living disks are NAND SLC, their rewrite cycle life is 100 000 times, but they are incredibly expensive and rarely found on store shelves. Discs MLC much more common. They are much cheaper, but at the same time slower. Rewrite cycle resource MLC-disks is approximately 3000 once. The cheapest, slowest and shortest-lived SSD-discs are made using technology NAND TLC, but even they have a resource that is quite acceptable by the standards of the average user. Number of rewrite cycles TLC-disks is approximately 1000 once.

You can determine the type of drive using the program AIDA64 (Data storage -> Physical disks-> Flash memory type) , although not always. Knowing the type, we determine offhand the life expectancy of the disk by applying a simplified formula. The method, to be honest, is not particularly suitable, since it does not take into account a number of indicators. Let's say you have TLC- disk volume 120 GB, which is registered on average per day 10 GB data. We multiply a thousand cycles by 120 and divide by 10 , like this:

1000 * 120 / 10 = 12000

12000 - this is the number of days during which we will record on SSD By 10 GB daily. Divide by 365 and we get 32 year. In reality, this number is an order of magnitude smaller. To avoid regularly rewriting the same block, which would lead to its rapid death, when writing new data, the controller distributes it evenly throughout SSD. In effect, this means that more data is being written to the disk than is apparent to the user.

But wear leveling is not the only variable that determines life expectancy SSD. TRIM, the type of data being recorded and a number of other factors also have an impact. Therefore, we will correct our formula, assuming that the controller writes to the media in 10 times more data, which was taken with a large and very large margin.

1000 * 120 / 10 * 10 = 1200

Total, a little over three years. It’s not enough, but let’s not forget about the reserve we took, and besides, it’s unlikely that for such a small and "weak" TLC-you will burn the disc using 10 GB daily. Reduce the amount of information recorded to 5 GB per day and the disk will last at least six and a half years, which is quite normal for an average hard drive. With memory chips SLC, MLC And TLC Everything is more or less clear, but I would like more specifics. Needed TBW disk, which, unfortunately, not all manufacturers indicate SSD. Most limit themselves to mean time between failures (in hours), but is that much use?

So where to look for this very TBW?

If it is not listed on the disk itself or the documentation accompanying it, go to the manufacturer’s website and try to find it in technical specifications models. Let's look at everything using a disk as an example. KINGSTON SUV400S37240G volume 240 GB. Go to the site www.kingston.com, follow the links SSD -> .

And select the disk with our series - UV400. We hope it’s clear where we got it from. KINGSTON this is the name of the manufacturer followed by the letter S in line SUV400S37240G this is the designation of the series, and UV400- her number.

Click on it and carefully examine the contents of the window.

As you can see, the disk KINGSTON SUV400S37240G has type NAND TLC And TBW 100 TB, which is what we actually need.

Now we find out how much data has already been written to the disk. If your drive supports the new protocol NVM Express, the amount of recorded data will show (see Total Host Records field) .

It turned out to be empty...

Therefore, we used another utility - SSD-Z. The required data is indicated in the field "Bytes Written".

IN in this example This 76.22 GB, TBW the same disk is 100 TB, which means that you can still write more to it 99923.78 GB. Let's say that we begin to write to disk using 5 GB per day.

We divide 99923 on 5 and more on 365 and we get 54 year. Knowing the remaining resource and the amount of data recorded daily, it is easy to calculate the approximate lifetime SSD. There is, however, one problem. Does SSD-Z take into account the amount of data increased by the controller? Unlikely. Therefore, it is best to rely on data S.M.A.R.T., which, alas, cannot be extracted from all disk models. Okay, then we'll divide it 54 sky-high 10 and we get 5.4 years- service life of the average storage device. In general, you can safely double it.

Hello friends! The other day one of our regular readers asked good question. He asked To how to find out how much longer it will work or toHow to find out the working resource of its SSD. Also last week, other users asked more questions on this topic, for example:

Which The type of flash memory for SSD is better: NAND, 3D NAND, 3D V-NAND and NOR?

How to find out which memory chips a purchased SSD consists of ( SLC, MLC or TLC) and which memory is better?

What is the number of rewrite cycles or TBW?

For all these interesting questions we will answer in today's article.

How to find out how long your SSD will last

I’m not afraid to repeat myself and say that everything in a computer is important, including the solid-state drive. Before purchasing it, be sure to know the performance and service life of your future SSD. It’s easy for a novice user to get confused here, because instead of the deadline SSD services, on the Internet everyone is talking about somethingnumber of rewrite cycles. I'll explain. C ikl rewrite, this is rewriting the entire volume (all cells) solid state drive, but the controller uniformly rewrites cells. For our convenience, manufacturers indicate (calculate using a formula) not rewrite cycles, A total amount of data in terabytes that can be written to the drive. This volume is called - TBW(Total Bytes Written -Total bytes written). H The more disk capacity, the more TBW it has.Knowing TBW, you can accurately calculate the life of your solid state.TBW limit may vary on different SSDs at times!

• The rewriting resource of an SSD or TBW can only be found on the official website of the device manufacturer, but not all manufacturers indicate such data, so it is better to purchase a solid-state drive from those manufacturers who indicate it.

The performance and service life of an SSD depend on two things: the type chips NAND flash memory: (SLC, MLC, TLC) and controller with firmware. The price of the drive directly depends on them.

IN solid state drives There are two main types of Flash memory: NOR and NAND. NAND technology is faster and cheaper. NAND memory today improved. 3D memory appeared NAND and 3D V-NAND. If we take the market of SSDs currently offered on the market, then 5 percent belongs to 3D V-NAND, 15 percent 3D NAND, rest 80 percent NAND. DThese data have an error, but a small one.

In turn, Flash memory: NAND can have three types of memory chips: SLC, MLC and TLC. Today, flash memory-based SSDs are mostly sold. MLC and TLC. In terms of TLC and MLC, the SSDs offered on the market are 50/50.TLC memory has a lower TBW limit.

1. SLC- Single Level Cell - is the oldest and fastest of the three technologies. Has high performance, low power consumption, highest write speed and large TBW limit (total amount of data that can be written to the drive) . The cost of a solid state based on SLC memory chips is very expensive and it is very difficult to find a modern SSD with it.
2. MLC- Multi Level Cell – has lower cost, lower operating speed and lower TBW.
3. TLC- Three Level Cell – has even lower cost, lower operating speed and lessTBW, compared to MLC chips. Memory TLC has always been widely used in conventional flash drives, but with the advent of new technologies it has been possible to use it in solid-state drives.

In which program can you see the memory type of a solid-state drive: TLC and MLC

The AIDA64 program can show the type of SSD memory, official developer website https://www.aida64.com/

In the main program window, select "Data storage"

then select the SSD model, for example, I have three SSDs installed in my system and I will select the first one - Samsung 850 Evo 250GB. As you can see, the flash memory type of the drive is TLC.

The second Kingston SHSS37A/240G drive has a flash type MLC memory.

How to find out the resource of a solid-state drive

For example, let's find out the resource Kingston SHSS37A/240G.

Go to the official website of the device manufacturer https://www.hyperxgaming.com/ru

Select “Solid State Drives” --> “Savage”.

Capacity 240 GB

and we see the total amount of data (TBW) that can be written to a Kingston SHSS37A drive with a capacity of 240 GB - 306 TB.

Let's compare it with the Samsung 850 Evo 250GB drive.

Go to the official website of the manufacturer http://www.samsung.com/ru/ssd/all-ssd/

Check the item - SSD 850 Evo Sata III drive.

Capacity 240 GB and left-click on the SSD image.

"Show all characteristics"

We see the indicator at the very bottom. Recording resource: 75 TB.

It turns out that SSD Kingston SHSS37A/240G resource number of TBW rewrite cycles is four times greater.

If you have an OCZ SSD drive, then go to the website https://ocz.com/us/ssd/

How to find out the total amount of data that has already been written to a solid-state drive

In the main program window, select my Samsung SSD 850 Evo 250GB. In the “Total host records” item we see the volume of data recorded on the drive is 41.088 TB. If we compare this figure with the recording resource indicated on the official website: 75 TB, we can conclude that another 33 TB of data can be recorded on the SSD.

In the case of SSD Kingston SHSS37A/240G, the program CrystalDiskInfo cannot show the total volume of data recorded on the storage device.

In this case we will use SSD program- Z.

Official website of the developer http://aezay.dk/aezay/ssdz/

Download and run the program.

In the main window, in the “Bytes Written” item, we see the volume of data recorded on the drive is 43,902 TB.

If we compare this figure with the recording resource indicated on the official website: 306 TB, we can conclude that another 262 TB of data can be recorded on the SSD.

CrystalDiskInfo starting from version 7_0_5 can work with new disks that use the latest new NVM Express protocol (Toshiba OCZ RD400, Samsung 950 PRO, Samsung SM951). Previous version I’ve never seen such programs for discs.

3.12.2017.

15.11.2017. A new (already third) version has been added to the life tests, equipped with the most advanced 64-layer TLC 3D V-NAND. Such drives have begun to appear on store shelves instead of older versions with 48-layer memory, so another check of this model will clearly not be superfluous. Information about the status of the remaining tested drives has been updated.

2.11.2017 . Testing has ended, which ultimately set a record for endurance among SSDs based on planar flash memory with three-bit cells. Information about the status of the remaining test participants is brought up to date.

16.10.2017 . The next scheduled update of the material, within which all statistics on the SSD models participating in testing have been brought up to date. Also, many of the drives being tested have been replenished with the addition of a very interesting new product - . This SSD is of great interest because it uses the new 64-layer 3D TLC NAND, recently produced by Intel itself. This is the first progressive 3D memory drive with 64 layers included in our testing.

7.10.2017 . Another drive model has been added to testing, which has long been of interest to our readers. This is an oldie based on the SF-2281 controller and MLC memory. For some unknown reason, such an SSD is still sold in stores, despite the fact that the SandForce controller is already, scary to think, seven years old. At the same time, another drive, based on the Phison PS3111-S11 controller, completed its participation in the tests. For all other trial participants who continue to work, the data has been updated.

18.09.2017 . Due to numerous requests from readers, a new participant has been added to testing -. It is notable for the fact that it uses eMLC memory with a declared resource of 10 thousand rewrite cycles. Tests have been completed for two other models, and , whose endurance turned out to be low. The quick demise of the Plextor S3C was not at all surprising - this model uses low-grade TLC memory, but the poor result of the Transcend SSD230 with Micron's 3D TLC NAND makes one wonder. Are there any errors in SMI controller SM2258, or Micron is deliberately supplying defective flash memory chips to the open market. In any case, before the appearance additional information We recommend that you refrain from purchasing drives based on a combination of SMI SM2258 and Micron 3D TLC NAND: ADATA Ultimate SU800, HP S700 Pro, Smartbuy Climb, Transcend SSD230, etc.

3.09.2017 . Life tests The SSD is one year old. This is quite a long time, but the statistics of visits to this page indicate that interest in the topic of endurance of different models of solid-state drives still remains. And this means that testing will continue, and the material will continue to be updated twice a month. Data on the subjects' mileage is brought up to date.

17.08.2017 . Two high-quality and interesting models- And . Both of them showed very good result, a detailed analysis of which has been added to the material. In addition, the tests included two SSDs from the category of fresh new products - and. Information about tests passed by all other drives has been brought up to date.

3.08.2017

16.07.2017 . Another update of the material. He dropped out of the tests, but this did not stop him from setting an endurance record. Two new models based on the increasingly popular 3D TLC NAND have been added to the number of test participants: and. At the same time, all information about drives that continue to operate as part of test systems is brought up to date.

6.07.2017 . Information about testing has been brought up to date. The SATA SSD pair - and - reached their recording capacity limit and completed participation in testing. Detailed information about how this happened has been added to the corresponding section of the material. In the near future we will try to supplement the composition of the tested drives.

20.06.2017 . Information on the current status of the SSD has been updated. Over the past period of time, the NVMe drive has dropped out of testing; a section based on the results of its tests has been added to the third page.

4.06.2017 . Data on the status of tested drives has been updated.

16.05.2017 . There have been no drive failures since the last update of the article, so all changes relate to the current operating time of the tested models. However, in addition to this, a new participant was added to the tests - a reference drive on the very popular Phison S10 platform with MLC memory.

30.04.2017 . Data on the status of drives that are already undergoing wear tests has been updated. In addition to these, we have added a few more new SSDs, which readers have requested to include. There are five new participants at once: (based on Micron MLC 3D NAND), (bufferless, based on Micron TLC 3D NAND), (NVMe, based on Toshiba 15 nm MLC NAND), (based on SanDisk 15 nm TLC NAND) and ( bufferless, based on Toshiba 15nm TLC NAND).

16.04.2017 . Over the past two weeks since the last update, four drives dropped out of testing. And if at the same time they showed very decent practical reliability for models built on TLC memory, then the other two failed SSDs, and , confidently registered among the outsiders. A detailed story about this four has been moved to the final part of the article. Information on the current status of the remaining participants has been updated.

31.03.2017 . Tests have been completed for one more drive. He died from resource exhaustion, and information about him was moved to the obituaries section. Two new participants have been added to testing: a popular one, the reliability of which our readers have long asked to check, and a promising NVMe drive, which has finally begun to be supplied to Russia. Information about the operating time of all other living test participants has been updated.

15.03.2017 . Lots of updates. Firstly, two more drives completed testing: and . They set two records at once - for maximum and minimum endurance. Secondly, a new original SSD was included in the tests - based on TLC 3D NAND manufactured by Micron. Thirdly, we transferred all information about those drives that have already completed their life cycle to . And fourthly, information on all those SSDs that continue to work under load has been updated.

3.03.2017 . Data on the status of tested drives has been updated.

15.02.2017 . Data on the status of tested drives has been updated. At the request of readers, two new SSD models have been added to testing: and .

31.01.2017 . Another test drive has exhausted its service life - . The section dedicated to him has been moved to the chapter "". Instead, added to testing new product Toshiba company - drive. Data on the status of the remaining tested drives has been updated.

15.01.2017 . Data on the status of tested drives has been updated. In addition, due to the increased interest in our test, there was a large-scale update of the composition of testing participants. Six new SSDs have been added to their number: , and . We continue to listen to the opinions of readers, and in the near future we will recruit SSD testing will be added again.

6.01.2017 .Two of the drives participating in testing ( and ) have exhausted their service life. Detailed analysis their life cycle placed in the "" section. In the final part of the article, an updated summary diagram with a practical resource was added, which was shown by test participants who passed the test. Data on the status of the remaining tested drives has been updated. In addition, the set of SSDs undergoing testing is expected to be replenished in the near future.

1.12.2016 . Data on the status of tested drives has been updated. In addition, as part of the ongoing research, we decided to conduct another experiment related to the study of SSD endurance. They will spend the next two weeks switched off. In this way, we will check whether the worn-out flash memory is capable of storing data at complete rest, when it is in a de-energized state and is not monitored by the controller.

15.11.2016 . Data on the status of tested drives has been updated.

30.10.2016 . Data on the status of tested drives has been updated.

15.10.2016 . Data on the status of tested drives has been updated. A new drive has been added to testing - a 32-layer TLC 3D NAND from Micron.

30.09.2016 . Data on the status of tested drives has been updated.

15.09.2016 . Data on the current status of the tested drives has been updated.

1.09.2016 . First version.

The Crucial BX500 is a new consumer drive that Micron aims to capture at the bottom end of the SATA SSD market. Because of its cheapness, there were even rumors that it uses QLC 3D NAND, but in reality this turned out not to be the case. The BX500 is a typical bufferless memory SSD with three-bit cells based on the SMI SM2258XT controller. The flash memory that underlies the BX500 is Micron's second-generation 64-layer TLC 3D NAND, which is used, for example, in the higher-end drive, the MX500. This means that despite being cheap, the new Crucial BX500 can be quite durable.

Endurance testing of the Crucial BX500 240GB continues. The current status of the drive is shown in the screenshot.

• The volume of recordings transferred by the drive is 958 TB. This is an order of magnitude higher than the stated resource of 80 TB, but you can expect much better endurance from the BX500. Thus, based on the same 64-layer TLC 3D NAND, the Crucial MX500 drive was able to transfer 1 PB of rewrites.
• According to S.M.A.R.T., the flash memory of the drive does not have any problems. Zero values ​​are stored by variables 01 (Raw Read Error Rate) - the number of read errors, 05 (Reallocated NAND Blocks) - the number of reassigned blocks, AB (Program Fail Count) - the number of write errors and AC (Erase Fail Count) - the number of data erase errors.
• The average number of programming-erase cycles for TLC 3D NAND cells is currently 4306. The drive controller evaluates this as complete resource exhaustion. Not surprising: the BX500 firmware states that TLC 3D NAND memory should only withstand 1500 rewrite cycles.

GOODRAM CX300 is a representative of a whole class of budget drives that have flooded store shelves in recent months. Distinctive feature These SSDs feature a bufferless design and use the Phison S11 platform. The GOODRAM variant is also additionally interesting in that it is based on Micron’s new 32-layer TLC 3D NAND, which makes it similar to drives such as the Corsair LE200, GALAX Gamer L, PNY CS3111b, Silicon Power S55 etc. Bufferless platforms typically have less than impressive endurance, but what about this particular case?

Endurance testing of GOODRAM CX300 240 GB continues. The current status of the drive is shown in the screenshot.

The given data can be deciphered as follows:

• The volume of records transferred so far is 2575 TB. And that appears to be close to the limit of this SSD's capabilities. Typically, SSDs built on Micron's 3D TLC memory carry 2 to 3 PB of writes, and here we see further evidence of this.
• As practice shows, the main S.M.A.R.T. attribute by which you should monitor the state of the flash memory array of drives based on Phison controllers is AA (Bad Block Count). To date, this variable has recorded 32 errors that have appeared during operation. Problems began to arise after 2.4 PB of data was written to the drive, and apparently their number will now grow rapidly.
• The average number of flash memory cell rewrites is 10,669 (encoded in the AD parameter). This value is evaluated in S.M.A.R.T. as complete wear of the drive (see parameter E7, which indicates the remaining resource as a percentage). GOODRAM believes that Micron's TLC 3D NAND was rated for 1000 write cycles. Micron itself talks about a resource of 1500 programming-erase cycles. But as can be seen from the test results, the resource value of both GOODRAM and Micron is taken into account with a large tolerance. For example, when testing the Crucial MX300, such memory was able to withstand approximately 10 thousand rewrite cycles.

Kingston A1000 is one of the most popular NVMe SSDs. That is why we included it in the test, although we must admit that its real performance is not at all as high as that of other NVMe SSDs, since Kingston chose a stripped-down Phison E8 controller for its product with support for only two lanes PCI Express. The secret of the demand for Kingston's offer lies in its low cost. However, such products usually raise suspicions: if the price is lower than that of competitors, has the manufacturer saved on something significant, for example, on the quality of memory? Moreover, this drive is based on Toshiba’s three-dimensional BiCS3 memory (TLC 3D), which manifests itself in very different ways.

Testing of the Kingston A1000 240 GB continues. The current status of the drive is shown in the screenshot.

The given data can be deciphered as follows:

• 968 TB. A resource of 150 TB is declared for the drive, but on average an SSD with a similar 64-layer TLC 3D NAND manufactured by Toshiba can in practice transfer about 750 TB of rewriting.
• No evidence of flash array degradation in S.M.A.R.T variables. 0E (Media and Data Integrity Errors) and 03 (Available Spare) are not included. The flash memory cells are in a completely “healthy” state, which is not surprising given such a mileage.
• The drive's flash memory cells are currently overwritten an average of 3,822 times. In S.M.A.R.T. it is believed that the flash memory resource has already been exhausted, which is not surprising, since according to the specification, the TLC flash memory used is designed for 3 thousand program-erase cycles.

The Russian brand Smartbuy continues to provide us with very interesting products to test. This time we took for testing budget storage Smartbuy Leap, which uses 32-layer MLC 3D NAND from Micron, which performs well in other drives. However, Leap received special attention because it is an ultra-budget model based on the Marvell 88NV1120 bufferless controller. It seems that this SSD should be recommended to those who are on a limited budget, but at the same time put data storage reliability at the top of their list. You just need to check whether Leap is really as durable as it seems and as its manufacturer promises.

Endurance testing of Smartbuy Leap 256 GB continues. The current status of the drive is shown in the screenshot.

The given data can be deciphered as follows:

• The volume of the transferred record is 2661 TB. This is already more than the manufacturer’s announced resource of 768 TB of rewriting, but less than the practical resource shown by other SSDs based on the same 32-layer MLC 3D NAND from Micron: ADATA XPG SX950 and ADATA Ultimate SU900.
• The number of reassigned sectors is 0, that is, the state of the flash memory array can be assessed as excellent.
• The average number of rewrites of flash memory cells is 11,187. In the Smartbuy Leap S.M.A.R.T. diagnostics, this mileage is not interpreted in any way, but Micron claims a guaranteed resource of 3 thousand programming-erase cycles for its MLC 3D NAND. However, this is also a very underestimate: in other drives such memory can withstand tens of thousands of overwrites without any problems.

⇡ Reliability of data storage on disconnected SSDs

Along with testing the rewriting resource, we also checked whether drives that have exhausted the resource declared by the manufacturer are capable of reliably storing data when turned off. There is a large number misunderstandings, so at one point we decided to stop the cyclic endurance testing for two weeks and see if the consumer SSDs aged in our test could retain the data recorded on them for a long time when the power was turned off. Thus, six drive models took part in this test, the operating time of which is several times higher than the endurance indicators declared by the manufacturers.

• Crucial MX300 275 GB after recording 487 TB of information;
• KingDian S280 240 GB after recording 578 TB of information;
• OCZ Trion 150 240 GB after recording 640 TB of information;
• Plextor M7V 256 GB after recording 1026 TB of information;
• Samsung 850 PRO 256 GB after recording 1049 TB of information;
• Samsung 850 EVO 250 GB second generation after recording 1969 TB of information.

Two weeks of being in a de-energized state did not affect the safety of the recorded data. SSD information absolutely no influence. All six drives were able to read both the information recorded immediately before shutdown, and those files that were stored on them from the very beginning of our endurance test. However, there are no failures or discrepancies in checksums was not recorded.

However, we still cannot say that a two-week stay without connecting to power had any effect on the drives. For two of the six models, a long downtime caused some changes in the flash memory array, which was reflected in S.M.A.R.T. telemetry.

In other words, the “aging” process continues in SSDs even when they are de-energized. However, no catastrophic changes occur. The test showed that a relatively long downtime of SSDs that have long since exhausted their entire declared resource does not lead to them breaking down or losing stored data.

But in fact, no one expected anything else. The test was carried out only because some time ago a strange belief began to spread that when turned off, solid-state drives very quickly lose their ability to reliably store data. Moreover, many near-technical sites have seriously contributed to the spread of this misconception, distributing and sometimes stubbornly continuing to relish the information that SSDs that are not connected to power can lose recorded data for almost several days.

In reality, this problem is blown out of nowhere. Of course, the process of charge flowing from flash memory cells when the drive is disconnected from power does occur, but it occurs much more slowly, and there can be no talk of any possibility of data loss within days.

As confirmation, you can refer to the specifications of JEDEC, a committee that includes all leading semiconductor manufacturers and which develops uniform standards for products in the microelectronics industry. These standards, on the one hand, are mandatory for manufacturers, and on the other hand, they are a guideline for customers, since they describe the main consumer qualities of devices produced by the industry.

Actually, the source of the panic about the safety of information on switched off SSDs was a table “taken out of context”, taken from one of the presentations of this committee, which indicated the “storage periods” of data on switched off drives depending on the ambient temperature.

NAND memory, the principle of which is to retain electrons in a floating gate, does indeed gradually lose its stored charge when at rest (without periodic updating). And sooner or later this can result in incorrect interpretation of the contents of the cell and loss of data. Ideas about how and how quickly the process of charge flow occurs are very well defined and supported by numerous experiments. Accumulated evidence shows that one of the main factors that affects the stability of NAND cells is their degree of wear. Therefore, the ability of SSDs to retain information when turned off is highly dependent on the stage of their life cycle at which they are located. The numbers given in the table above describe the situation with exhausted drives, and not with new ones - and this changes almost everything.

In other words, if we are talking about a new SSD, then the data on it can be stored for years when turned off (at the usual temperature range). And only when it comes to a drive that has already exhausted the resource specified by the manufacturer, the “shelf life” specified in the specification begins to make some sense. That is, 52 weeks (year) is the minimum period of time during which a regular consumer drive is required, according to the specification, to store data in the off state after it has already exhausted the entire resource defined in the specifications. But in fact, information will most likely be able to last much longer on a switched off SSD: as we have seen, manufacturers indicate the rewriting resource with a multiple reserve. And the situation with shelf life is most likely about the same.

If we delve further into the JEDEC specifications, we can find another confirmation that even after significantly exceeding the stated overwrite limit, drives are not subject to rapid loss of information recorded on them. While consumer SSDs have a minimum storage life of one year (at 30 degrees), server models, which are usually based on exactly the same flash memory, this time interval is narrowed to 3 months (at a temperature of 40 degrees).

The difference is due to the fact that consumer and server SSDs are subject to loads that differ in intensity. The declared endurance of consumer drives is usually several tens or hundreds of terabytes of rewriting. SSDs belonging to the server class have an order of magnitude higher declared reliability, which reaches units or even tens of petabytes of rewriting. It follows from this that even after writing to a regular SSD an amount of data that significantly exceeds its resource, it will not lose the ability to store it in a switched off state for at least several months - by analogy with the server model.

That is why our two-week check of information security in a switched off state did not reveal any problems. After overwriting hundreds of terabytes, modern SSDs are simply required to retain data for much longer than a couple of weeks. And it is clear that JEDEC specifications are being followed by manufacturers in this regard.

At this point, we consider the issue of information safety on a switched off SSD closed. It is clear that testing the rewrite resource is a much more important from a practical point of view and a more meaningful experiment, which can say much more about the endurance of modern solid-state drives. In addition, our testing methodology also checks the correctness of reading files stored on the SSD at the very beginning of the experiment.

However, we consider it our duty to remind you that NAND memory drives are not intended for archival storage of information. Magnetic storage media - hard drives and tape drives - look more suitable choice for this purpose. SSD, on the other hand, is a fast storage medium, aimed primarily at working with “hot” data.

When choosing a disk for their system, users increasingly give SSD preference. Typically, this is influenced by two parameters - high speed and excellent reliability. However, there is one more, no less important parameter is the service life. And today we will try to find out how long a solid-state drive can last.

Before calculating how long a drive will last, let's talk a little about the types of SSD memory. As you know, currently, three types of flash memory are used to store information - SLC, MLC and TLC. All information in these types is stored in special cells, which can contain one, two or three bits, respectively. Thus, all types of memory differ in both data recording density and the speed of reading and writing them. One more important difference is the number of rewrite cycles. It is this parameter that determines the service life of the disk.

Formula for calculating drive life

Now let's see how long an SSD with the type of MLC memory used can last. Since this is the memory most often used in solid-state drives, we will take it as an example. Knowing the number of rewrite cycles, calculating the number of days, months or years of work will not be difficult. To do this, we use a simple formula:

Number of cycles * Disk capacity / Amount of recorded information per day

As a result, we will get the number of days.

Service life calculation

So let's get started. According to technical data, the average number of rewrite cycles is 3,000. For example, let's take a 128 GB drive and the average daily volume of data written is 20 GB. Now we apply our formula and get the following result:

3000 * 128 / 20 = 19200 days

To make it easier to understand the information, let’s convert days to years. To do this, divide the resulting number of days by 365 (the number of days in a year) and get approximately 52 years. However, this number is theoretical. In practice, the service life will be much shorter. Due to the features of the SSD, the average daily volume of recorded data increases by 10 times, so our calculation can be reduced by the same amount.

As a result, we get 5.2 years. However, this does not mean that after five years your drive will simply stop working. Everything will depend on how intensively you use your SSD. It is for this reason that some manufacturers indicate the total amount of data written to the disk as the service life. For example, for X25-M drives, Intel company provides a guarantee for a data volume of 37 TB, which at 20 GB per day gives a period of five years.

Conclusion

To summarize, let's say that the service life depends quite strongly on the intensity of use of the drive. Also, based on the formula, the volume of the data storage device itself plays an important role. If we compare with HDDs, which last about 6 years on average, then SSDs are not only more reliable, but will also last longer for their owner.

Dumansky Maxim Vladimirovich 23695

When it comes to solid-state drives (SSDs), you often hear opinions about their unreliability and fragility from people who were interested in purchasing them, but came across information about the limited number of rewrite cycles of the flash memory of the drive, which scared them.

Let's try to figure it out with information to the end and confirm or refute this opinion. First, let's look at the design of an SSD drive. It is a non-mechanical storage device, the word “non-mechanical” means that its design has no moving parts, no motor, no spindle, no plates, no heads. Its entire contents are Flash memory blocks and a controller that controls recording.

With the development of storage devices, flash memory has changed to faster and cheaper ones. Initially, at the dawn of their appearance, SSDs had a small volume and were inferior to traditional HDDs in write speed, but they more than compensated for this quick search information, because access to it is not slowed down by the physical movement of the magnetic heads. But in modern solid-state drives the situation has changed and this speed is much higher than the capabilities of the HDD. This is due to many factors, the development of write controllers and, in particular, the evolution of flash memory itself.

Initially, SLC (single-layer cell) type memory was used; it is expensive, but quite slow and has a resource of about 100,000 rewrite cycles. Then it was replaced by MLC type memory (multi-layer cell), cheaper, faster, with a limit on the number of cell rewrite cycles of about 10,000, now this is the most common type of memory used in SSD drives. Less common yet newest type flash memory – TLC (triple-layer cell, three-level cell), developed by Toshiba and used in top models of SSD drives, in particular in the M5 PRO series of Plextor drives, which, in addition to “fashionable” memory, also feature a Marvell recording controller with its own , modified, firmware. TLC differs from the previous two types in that it stores not 2, but 3 bits of memory in one cell, which increases the recording density and speed of access to information.

But let's return to the question of the lifespan of memory. For TLC, the manufacturer (Toshiba) does not indicate the number of rewrite cycles, but for me personally, and I have an M5 Pro with this type of memory in my laptop, a five-year warranty from Plextor is quite enough (see the “round” in the packaging photo above). The fact is that in five years I have had a new computer and three laptops, so does it matter to me what hard drive was in the computer or the first laptop five years ago? Moreover, even after the rewrite cycles have expired, in the difficult foreseeable future, all information on the SSD will be available for at least another year in read mode.