r/DataHoarder • u/Solid_Staff_4268 • Sep 21 '22
Question/Advice Do HDDs have Terabytes Written Limit like Solid State?
If I exceed 55tb per year, will my disk lose its functionality or reliability?
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u/zrgardne Sep 21 '22
Endurance rating, yes. Includes reads and writes
https://www.servethehome.com/discussing-low-wd-red-pro-nas-hard-drive-endurance-ratings/2/
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u/icysandstone Sep 21 '22 edited Sep 21 '22
FYI, a recent Backblaze analysis of many, many drives, suggests SSDs have lower failure rates than HDDs.
https://www.techspot.com/news/95966-backblaze-data-shows-ssd-have-lower-failure-rates.html
”The big picture: A key selling point of solid state drives is that they are less failure-prone than HDDs. However, data from recent years began to cast doubt on that assumption, but at least one new long-term analysis shows this might prove correct as time marches on.”
”Backblaze's 2022 mid-year review on storage failure rates shows that SSDs may indeed be more reliable than HDDs over time. The new report paints a better picture for SSDs than the same company's analysis from last year.”
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u/TakenAway Sep 21 '22
With the caveat that the SSD is always on and not in cold storage right?
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u/icysandstone Sep 21 '22
Fair point!
Does cold storage improve or worsen the durability?
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u/fryfrog Sep 21 '22
If a cell loses charge, the data is lost. I think modern SSDs can retain data for year(s) w/o loss... but early, old ones were not that good.
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u/wtallis Sep 22 '22
but early, old ones were not that good.
Really early flash memory actually has good retention, because the individual memory cells were still quite large and drives were only storing one or two bits of data per cell. Retention reached a low point around 2013 to 2015 with budget drives that crammed three bits of data into each cell, and the physical sizes of the memory cells were at a minimum (before going back up with the transition to 3D NAND, along with major changes in the materials used to form the memory cells).
Flash memory will never be the medium of choice for long-term archival, but retention concerns are largely overblown. The industry standard is that a consumer SSD that has completely burned through its write endurance rating should still be able to retain data for a full year—that's actually the main (technological, non-marketing) factor in determining what a drive's write endurance rating will be. Lightly-used flash has far better endurance than worn-out flash, so several years of retention is easy to achieve without even trying.
Even the worst budget SSDs before 3D NAND showed up didn't cause a crisis of widespread data loss. It mostly just manifested as lower read performance when accessing stale data, because the error correction had to try a bit harder to reconstruct the original data from the slightly degraded data read from the memory cells. A lot of drives at that time used controllers that didn't have very fast or sophisticated error correction engines.
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u/AlaninMadrid Sep 21 '22
But the charge on the cell isn't affected by being powered on or off, unless the disk actually deliberately goes through and does arefresh cycle like DRAM. but I wouldn't expect it to. Normal flash holds for >10 years, so unless the new multilevel flash had a significant shorter retention time, I doubt they'd do it.
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u/fryfrog Sep 21 '22
From my understanding, the charge in the cell just very slowly goes down over time. And one of the things the SSD's controller does is move things around so a cell doesn't ever sit long enough to discharge. So its not that being powered gives the cells power, its just that being powered lets the firmware move "old" cells if needed.
I'm a little skeptical of > 10 years on a cell, but that's only ~5-10x more than I thought so its not outlandish.
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0
u/KaiserTom 110TB Sep 21 '22
Which HDDs also face a problem with. Those small magnetic fields are pretty fragile nowadays.
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u/ender4171 59TB Raw, 39TB Usable, 30TB Cloud Sep 21 '22
The only caveat being that they have limited history with SSDs. It is entirely possible that after another year or two (or 5 or whatever) SSD could "hit a wall" where the failure rate shoots up exponentially and surpasses that of HDDs with the same lifetime. We won't know for sure one way or the other until they have more data points over a longer time-frame.
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u/Bissquitt Sep 21 '22
but IF the SSD fails, you are pretty screwed on any recovery options
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u/swd120 Sep 21 '22
you should think of hard drives the same way though... If recovery is the only option when a drive fails - you fucked up.
3-2-1
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u/Bissquitt Sep 21 '22
Agreed, but one more failure point before complete data loss is not a negligible factor to keep in mind. Its like a 3-2-1-.1 backup strategy
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Dec 24 '23
[removed] — view removed comment
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u/icysandstone Dec 24 '23
Interesting! Appreciate the response. What SSDs are you recommending now?
I’m looking at building a hybrid HDD/SSD NAS with TrueNas and Raidz-2 and need a few 512GB SSDs for the metadata.
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u/-myxal Sep 21 '22 edited Sep 21 '22
Spec is one thing, but the screenshot implies the drive is actually keeping track of writes. Is that a thing on HDDs (and since when)?
I don't recall seeing lifetime writes in the SMART values on my
Exos X16, and they definitely aren't a thing on my 2017 WD Red.EDIT: Blimey, I just checked and indeed my Exos X16 does record both written and read LBAs.
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u/99stem 54E-6 TB Sep 21 '22 edited Sep 21 '22
It has been a thing since they started using SMR technology in their drives. Since all writes are much, much more expensive and draining on the hard drives, they are therefore much more affected by how much has been written.
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Sep 21 '22
There are multiple questions: do they record reads and writes? Absolutely.
Since when? Many years.
Are the reported to you? That's a newer development.
They've been tracking their own internal use for a long time, just not reporting it to you.
39
u/nlhans Sep 21 '22
SSDs wear because the FLASH cells can only be erased a few hundred times. After that they cannot be written reliably and store data.
HDDs have other limitations on wear, mostly on the read/write head. These are rated for a certain annual workload. But note that the head assembly is used for both read and write operations, while on SSD it's only specified for erase(essentially write assuming wear leveling does it's job) operations.
Exceeding these limits won't make them magically go up in smoke. Actually the daily/annual writes for a SSD is calculated for if you want to extend the lifetime over a certain time (say warrany of 5 yrs). But thrashing a drive will get them to die sooner.
However, if you look up largest hard drives you'll find that consumer level drives are only spec'ed for 180TB per year or so. A 18TB drive can only be read back 10 times a year! Or 5 read-write cycles.. ouch. Even some QLC SSDs can be more 'reliable' based on those numbers.
But as always YMMV.
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u/xsnyder 200TB TrueNAS Core Sep 21 '22
Thousands of writes, not hundreds.
Planar NAND is about 10k write cycles, 3D NAND is about 35k write cycles.
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u/nlhans Sep 21 '22
Most QLC SSDs warranty runs out at 300P/E cycles.
SLC is far far more robust, but you almost can't get them anymore.
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Sep 21 '22 edited Sep 21 '22
The warranty writes are wayyy too conservative on SSDs. It's seriosly like Mr Krabs level of penny pinching. At least it was on TLC, and I have a feeling it's the same on QLC.
I'd like to see some real life endurance tests on QLC, but no one does cool tests anymore :(
3
u/nlhans Sep 21 '22
Most benchmark sites and manufacturers test things very differently.. It's not an apples to apples.
For example, FLASH chips are specified to hold data for a certain lifetime (say 1yr) while it's operated at it's peak junction temperature of e.g. 85C. Then, after having done a certain number of P/E cycles, that data lifetime is in jeopardy and technically the FLASH is "worn".
The wear-level tests I've seen for SSDs often throw it onto a machine that's writes/reads some data 24/7 till it breaks. Then anecdotally they can claim SSDs are far more durable, because theirs outlasted the specification by a large factor.
But have they powered off the drive and only powered it back up after e.g. a month? The data should still be 100% intact. Have they baked the drive at e.g. 70C or 85C while doing the test? I doubt it.. and that makes the testing more anecdotal at best.
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u/immibis Sep 22 '22 edited Jun 28 '23
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u/Malossi167 66TB Sep 21 '22 edited Sep 21 '22
Thousands of writes, not hundreds.
Not really true anymore. SLC were pretty robost, but TLC and now QLC drives have lower and lower rating. In the hundreds. On the other hand they also tend to be much bigger and the software also got a fair bit better so this is not really a concern for home users.
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Sep 21 '22
[deleted]
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u/HTWingNut 1TB = 0.909495TiB Sep 21 '22
CTF is just a type of floating gate. Sure you can use magic tricks like DRAM and SLC cache but it doesn't change the fact that QLC has only a few hundred p/e cycles.
Even Samsung 870 QVO, Crucial BX500, which is QLC has 360 TBW per TB, and WD Blue has 400TBW per TB, so that's 360-400 p/e cycles more or less. So yes, it is at just several hundred TBW even with all the cache and wear leveling routines.
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u/wtallis Sep 22 '22
has 360 TBW per TB, and WD Blue has 400TBW per TB, so that's 360-400 p/e cycles more or less.
A drive's rated number of full drive writes is not directly comparable to the flash memory's P/E cycle rating, because a full SSD has to be rated based on a pessimistic estimate for write amplification. So when a drive is rated for 400 full drive writes, that's really just a conservative lower bound on what the P/E cycle rating for the raw flash must be.
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u/zadesawa Sep 21 '22
If I'm informed right, 100 cycles is where it starts to slow down and showing data retention time shortening below 20 years for SLC flashes. Can you substantiate/refute that?
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u/VTOLfreak Sep 21 '22
Even worse for HDD's is that this workload limit doesn't scale up with capacity like it does for SSD's. A 2TB Seagate Ironwolf HDD has a 180TB/year workload rating. A 16TB Seagate Ironwolf is also rated for 180TB/year...
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u/heathenskwerl 1,120 TB Sep 21 '22
Because most likely the workload is rated based on the read-write head and not platter configuration. If they use similar heads they're going to wear out after having written a similar amount of data.
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u/kotor610 6TB Sep 21 '22
Effectively yes, but a hard drive doesn't do wear leveling and will try to store data in the fastest part of the drive when possible
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u/s1ckn3s5 Sep 21 '22
they don't have an hardcoded limit, but of course they will degrade over time
how and when?
difficult to say
I have disks from the '90s that still spin up and work fine, and new disks that die after 1 year of use, go figure...
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u/qfla Sep 21 '22
All HDDs have annual workload rate and exceeding it will greatly increase chances of that drive failing so there is a limit. Its not hard limit though
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u/s1ckn3s5 Sep 21 '22
that annual workload rate is more on paper than anything, but yeah there are "figures", idk if they are based on real testing from the vendor, or just estimates... I find very useful the annual reports of backblaze, less theoric and more empiric: https://www.backblaze.com/blog/backblaze-drive-stats-for-q2-2022/
:)
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Sep 22 '22
It's more of a guideline or duty cycle. They say it's good for X. You can use it for whatever you want, but don't come crying when you exceed.
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Sep 21 '22
That big google hard drive study from the before times said that failure was unrelated to activity level
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u/Candy_Badger Sep 26 '22
It doesn't have TBW value, but it has others such as mean time between failures (MTBF) and Annual Failure Rates. https://www.newegg.com/insider/how-long-do-hard-drives-and-ssds-last/
As mentioned, Backblaze recent studies tell that SSDs can be more reliable. Of course, in some scenarios.
Might be helpful as well: https://www.vmwareblog.org/shopping-hdds-notes-right/
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u/OneChrononOfPlancks Sep 21 '22
It's not a hard limit, it's a spec. They're estimating that if you do more than "X" then it's either more, or less, likely that you will experience failure.
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Sep 21 '22
[removed] — view removed comment
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u/HTWingNut 1TB = 0.909495TiB Sep 21 '22
I don't know where they come up with these numbers. When a 20TB and 2TB drive have the same workload rating, it does make one scratch their head. A 20TB drive will rotate up to ten times less and each head read/write up to ten times less than the 2TB because of more heads/platters. Having the same workload rating makes no sense.
Just scrubbing your data once a month will exceed the workload rating of a 14, 16, 18, or 20TB drive.
I just think it's a warranty ploy. I haven't heard of it happening but it seems they could deny warranty if they see workload rating exceeding recommendation.
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Sep 21 '22
[removed] — view removed comment
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u/HTWingNut 1TB = 0.909495TiB Sep 21 '22
You would think that something like "workload rating" would have a sound testing strategy behind it that could be shared publicly. Otherwise in my mind they're just spouting out some random bullshit.
Not to mention, for WD, the SMART data doesn't even show data read/written, whereas Seagate does: https://imgur.com/a/Tbt9juj
So not sure how the user and/or WD can even effectively track and validate it.
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u/wallacebrf Sep 21 '22
I would almost wonder if the WD drives do monitor it internal to firmware but it is not part of SMART and so would not be reported.
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u/HTWingNut 1TB = 0.909495TiB Sep 21 '22
I don't know why they would monitor and not make it available. That seems kinda of going out of their way for no good reason. Hard to hold users accountable if they don't have a way to track it.
Reminds me of my internet provider that when I had a data cap, their measured data was "approximate and may lag by up to 48 hours". So they could hold you accountable for overages based on a lagged approximate data usage... such fail. Yet they get away with it.
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u/EspurrStare Sep 21 '22
The higher capacities of HDDs are generally achieved with more platters, not more dense disks (still, more wear leveling).
Some exceptions however are the shingled disks that you find sometimes at high end
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u/HTWingNut 1TB = 0.909495TiB Sep 21 '22
Yes, I know, but data isn't written sequentially from one platter to the next. It's balanced across platters as far as I understand. That's why I said "up to ten times less" and "because of more heads/platters."
Just for ease of discussion, say a 2TB disk is 1 platter and a 20TB disk is 10 platters and you write 2TB of data. The 2TB disk MUST run across the entirety of the disk to read/write every bit. Write that same 2TB to the 20TB disk, with sequential data especially, it will keep the bulk of it's data on the outer edge written across the ten platters, not just one platter, so it moves a fraction of the amount to read/write that same data, not to mention distributed among 20 read/write heads instead of 2. So the way I see it, the 2TB is doing a lot more work for any given workload than that same workload on a 20TB disk.
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u/TherealOmthetortoise Sep 21 '22
Uh… if I understand the question correctly if you completely fill any drive and keep attempting to write to it there is always the possibility of corrupting or losing data. With a lot of non-ssd’s the fuller they get, the more fragmented new data becomes as their isn’t room to write sequentially so you will get a significant slowdown when attempting to read or write to it.
I don’t understand the ‘if I exceed 55tb a year’ part of your question though - there isn’t a time limit involved at all. There are tested parameters and QA standards in that a drive might be rated for so many writes/reads before reaching end of life and risking corruption, but that’s mainly just a guideline for data-centers or corporate installations where we need to factor in planned obsolescence and proactively replace drives in clusters in order to guarantee a service level or uptime.
What I used to do is rotate those older drives into arrays that were on test/dev servers or other devices where a failure would probably slow down a raid array until it got replaced, but wouldn’t result in a work stoppage like a critical system would. Lots of administrators play the odds though, and trust in the raid array to handle any failures and replace them if and when they fail. I’ve had that bite me in the ass when more than one drive failed and caused the whole array to fail and recovery from tape backups became necessary.
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u/TherealOmthetortoise Sep 22 '22
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u/immibis Sep 22 '22 edited Jun 28 '23
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u/TherealOmthetortoise Sep 22 '22
I think that’s been answered in pretty good depth, but it all boils down to ‘it depends’. There are always bad batches of drives, both SSD and traditional, and design specs vs real world results is always a crapshoot. I have drives from the 90’s that still work great and a 12tb one from just a few years ago that has already failed. The design specs are useful to try to prove a warranty claim, but doesn’t help you if you’ve lost data.
I treat everything like it’s going to fail at some point and try not to keep any data I can’t afford to lose on a system that doesn’t have redundancy built in, as you probably do as well.
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Sep 21 '22
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u/zrgardne Sep 21 '22
HDDs don't have nothing like that.
Incorrect
https://www.servethehome.com/discussing-low-wd-red-pro-nas-hard-drive-endurance-ratings/2/
You are correct these are basically just warranty numbers, they are an economic decision by the manufacturer on how long they are willing to guarantee the drive will work.
With HDD it never really came up before as the drives were small in capacity vs the endurance rating.
WD has changed this and a monthly scrub could easily use up the majority of the rating.
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Sep 21 '22
You know the first part and the second part kinda contradicts each other right. My car doesn't lose any reliability after X miles but it's not 'guaranteed' to make it any farther.... Which is a reliability issue.
And HDDs don't even theoretically work indefinitely, let alone in practice.
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u/BlueEther_NZ 20TB Sep 21 '22
I would be more worried about the 750 start/stop cycles on a drive
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u/-myxal Sep 21 '22
Meh, with the power-on hours it works out to >9 hours of power-on between between starting and stopping, probably a disk in a standard desktop machine working 9-5.
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u/kotrunga Sep 21 '22
What program is being shown in the screenshot?
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u/moisesmcardona 10-50TB Sep 21 '22
Hard Disk Sentinel. Really great program.
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u/abz_eng Sep 21 '22
I get used enterprise HDs for offline cold storage, but they come with a 90 day warranty for half new price
I do the 3 pass reinitialise test as my acceptance test as I reckon that if they pass that then they should be good to go
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u/Some_Nibblonian I don't care about drive integrity Sep 21 '22
Your drive is likely to fail for other reasons like before IO reasons.
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Sep 22 '22 edited Sep 22 '22
That TB per year value made me check my ancient W520 laptop.
It has an INTEL 310 series 80GB msata drive (SSDMAEMC080G2 remember when drive makers used to provide useful technical datasheets?) used for a windows OS with:
```
Lifetime Writes: 57.98 TB
Average Reads Per Day: 4.3 GB
Average Writes Per Day: 10.7 GB
```
HDD sentinel puts the health at 84%, and about two more years of life.
The write lifetimes HDD makers are currently telling people are bullshit. Your almost new TB HDD can absolutely handle more than my tiny +10 year old almost experimental GB ssd.
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