SSD Wear

[troll]

Hi, I have a question about SSD endurance. If your SSD has an endurance of 100TB and you've written 10TB, am I right in assuming that is 10% wear and 90% remaining?

I say this because I have a drive that has only had 10TB out of 100TB written but the SMART is showing 30% wear.

 

[Armageus]

Yes but no.

It can depend on how the wear level is calculated, as some manufacturers calculate it differently.

It is also affected by write amplification - where lots of small writes can cause bigger "pages" of flash to be erased and rewritten. So e.g. you might write 1KB to the drive, but as a result of having to erase an entire 4KB (or larger) page, the amount of data written can be amplified.


SSD Endurance is only a guideline however, used by manufacturers to provide a figure generally for warranty length - with most drives writing far more than the Endurance figures would suggest.

Write amplification - Wikipedia

en.wikipedia.org

EDIT:
It might be worth checking to see if your partition is correctly aligned, as if this is not correct, this will increase write amplification

How to Check and Run SSD Alignment in Windows 10?

How to know if the SSD partition in Windows 10 is well aligned? Here to find how to do SSD partition alignment via Diskpart and other partition alignment tools.

www.diskpart.com

 

[troll]

Yes but no.

It can depend on how the wear level is calculated, as some manufacturers calculate it differently.

It is also affected by write amplification - where lots of small writes can cause bigger "pages" of flash to be erased and rewritten. So e.g. you might write 1KB to the drive, but as a result of having to erase an entire 4KB (or larger) page, the amount of data written can be amplified.


SSD Endurance is only a guideline however, used by manufacturers to provide a figure generally for warranty length - with most drives writing far more than the Endurance figures would suggest.

Thanks for the detailed response.

When the SSD shows 100% used after 100TB, even though you should have 300TB left because the endurance is 400TBW, would you trust your data on it?

 

[dimension99]

I think they are a lot more reliable than people think, I have not heard that many reports of them failing due to wear? for example, I have an ocz Vertex 2 in my ESXI server, it has had VM's running from it since 2013 24x7 and is still working fine. I dont see any errors being reported about the disk
I also have one that was used for plotting files for Burst coin mining, this had over 100TB of writes to it and it is still working fine

 

[tamzzy]

would you trust your data on it?

in theory, once nand reaches its write lifespan, it should still be readable
you just cannot rewrite the nand

regardless, when an ssd dies, it is usually sudden and will take everything with it, not like a slow decline that is sometimes seen with standard hard drives
so backing up is always important

 

[EsaT]

in theory, once nand reaches its write lifespan, it should still be readable
you just cannot rewrite the nand

There's far more to it than that:
When Flash memory wears down, its data retention ability suffers.
And those so called write endurance tests ending up far above specified TBW did nothing to test that data would have survived without power.

So if there's some critical control/"internal book keeping" data on weaker cells, those bits might not be there after time without power.
Because for as long as drive is powered, controller can keep monitoring condition of the cells and rewrite data elsewhere, if raw signal approaches tolerances.
And hence you have that completely dead drive, which doesn't give any life signs again after losing power.
(+add possible firmware bugs comparable to serie of self bricking HDDs Seagate had once)

 

[mrk]

Blacklaze use SSDs and HDD mix for their cloud storage solutions and they do papers on failure rates. Their latest study found that SSDs are more reliable than HDDs.

My old Intel 730 series was far beyond its TBW after the 5th year of service before I sold it on, still at over 90% health. It was a 480GB SATA unit.

99% of people will never wear out a modern SSD in their lifetime and before they even get close, will be maxing the capacity anyway and be wanting an upgrade.

At this point we can reasonably claim that SSDs are more reliable than HDDs, at least when used as boot drives in our environment. This supports the anecdotal stories and educated guesses made by our readers over the past year or so. Well done.

The SSD Edition: 2022 Drive Stats Mid-year Review

Andy Klein's much anticipated 2022 SSD Midyear Drive Stats Report is here. Read on to see the findings.

www.backblaze.com

The time of the HDD for storage is coming to an end tbh, by 2030 Samsung's 1000 layer NAND will be in prduction and that is projected to support up to 1000TB. Currently the Nimbus SSDs carry up to 100TB or so, naturally you can figure the price of those things But storage prices are continuasly dropping and Q4 2022 is said to see eve further drops. My 8TB Samsung that was £660 this time last year is now £100-£200 cheaper for example depending on where you buy.

For maximum longevity and efficiency make sure to have at least 10% over provisioning space left for the drive to use when it needs it. You don't need to do anything special other than making sure 10% is not allocated to anything.