Solved Has anyone done extensive research into long term data storage on an SSD?

hsehestedt · Jul 25, 2022

Let me start by saying that I hate thumb drives. Even the "fast" ones annoy me. Don't get me wrong, they have their place, but I'm at a point where I have some fairly significant amounts of data that I want to put into long storage.

I'm considering going to NVMe SSDs for this purpose for a few reasons:

1) They are fast - a definite advantage considering that I have many TB of data to archive.
2) They have become what I would consider very affordable now. A good quality 500GB NVMe is now under $40 in the US.
3) They are very small, making organization and storage a breeze.

However, I have some serious questions about long term storage. I know that the specs say that an SSD should be able to retain data for a minimum of 1 year at 30 degrees C, but that retention time drops dramatically with even a few degrees in temperature.

So here is the big question: In order to "refresh" the cells on an SSD, do I merely need to plug the NVMe and give it power for a few seconds or does it need to remain plugged in for an extended period of time so that the controller can go about "touching" every cell on the SSD? I cannot seem to find an answer to this anywhere. If anyone has researched this and found an answer, I would appreciate it if you could share what you have found.

FreeBooter · Jul 25, 2022

Most SSDs will retain your data without power for 5 to 10 years. You will need to regenerate those cells every few years, other than that i don't see any problems using SSDs as storage drive.

Ghot · Jul 25, 2022

I hate to sound old fashioned, but a good hard drive will hold data... for a very long time.
I have a couple hard drives that have been holding data for almost 20 years now.

No maintenance required. Just don't drop them or bang them around too much. :)

SIW2 · Jul 25, 2022

DiskFresh - Refresh Hard Disk Signal

DigitalGoat · Jul 26, 2022

There is a very interesting article on Anandtech's site, referencing information from JEDEC and various manufacturers:
The Truth About SSD Data Retention

jimbo45 · Jul 26, 2022

hsehestedt said:
Let me start by saying that I hate thumb drives. Even the "fast" ones annoy me. Don't get me wrong, they have their place, but I'm at a point where I have some fairly significant amounts of data that I want to put into long storage.

I'm considering going to NVMe SSDs for this purpose for a few reasons:

1) They are fast - a definite advantage considering that I have many TB of data to archive.
2) They have become what I would consider very affordable now. A good quality 500GB NVMe is now under $40 in the US.
3) They are very small, making organization and storage a breeze.

However, I have some serious questions about long term storage. I know that the specs say that an SSD should be able to retain data for a minimum of 1 year at 30 degrees C, but that retention time drops dramatically with even a few degrees in temperature.

So here is the big question: In order to "refresh" the cells on an SSD, do I merely need to plug the NVMe and give it power for a few seconds or does it need to remain plugged in for an extended period of time so that the controller can go about "touching" every cell on the SSD? I cannot seem to find an answer to this anywhere. If anyone has researched this and found an answer, I would appreciate it if you could share what you have found.

For absolute long term storage -- but not sure if those are available any more - but if you have any left DVD RAM is probably the media with longest lifespan (approx 100 - 500 years) - but only 4.7GB per disc.

Bog standard high quality HDD's though are good enough -- the trick is always to duplicate stuff you really need to keep especially long term.

SSD's and NVME's haven't been around long enough yet for their suitability of long term storage either so it's still a guess on that one.

Cheers
jimbo

bobkn · Jul 26, 2022

jimbo45 said:
For absolute long term storage -- but not sure if those are available any more - but if you have any left DVD RAM is probably the media with longest lifespan (approx 100 - 500 years) - but only 4.7GB per disc.

(snip)

Cheers
jimbo

A quick Web search suggests 30 years for DVD-RAM, but longer for write-once discs. CLIR is the Council on Library and Information Resources, so presumably they care about digital archives.

M-disc claims a millenium.

I have a few 100GB M-Discs, which are too small. I doubt that my BluRay drive will continue to work for 1000 years, though. Or even 100.

DigitalGoat · Jul 27, 2022

bobkn said:
A quick Web search suggests 30 years for DVD-RAM, but longer for write-once discs. CLIR is the Council on Library and Information Resources, so presumably they care about digital archives.

M-disc claims a millenium.

I have a few 100GB M-Discs, which are too small. I doubt that my BluRay drive will continue to work for 1000 years, though. Or even 100.

And there is the rub, as the saying goes, it doesn't matter how long a medium claims it will last, the real issue is how long the technology will be around to read that medium, compounded by file formats, especially password protected and proprietary file formats.
It brings to mind an episode of an anime, Cowboy Beebop, in which the crew has to go on an adventure to find a Betamax player (just to make it harder) in order to view a tape passed down through the ages.

hsehestedt · Jul 27, 2022

My apologies to all. I may have given the wrong impression with my initial post.

I was not attempting to solicit comments on alternate forms of media to which I might consider backing up.

I already have strategies that include roughly 150 TB of HDDs and 4 TB of Blu-Ray media (that's a lot of Blu-Rays), the SSDs will serve a different purpose where extremely rapid access will be needed.

My research just led me to wondering exactly what needs to be done to "refresh" the electrical charge on an SSD. Since there is a limited amount of time that data can be retained on an SSD, be that 1 week, 1 year, 10 years, whatever, that's not even my main concern. I was simply curious whether the electrical charge gets recharged immediately when the SSD is connected to a source of power or whether the cells electrical charge only get refreshed as the controller performs its maintenance tasks and "touches" every cell on the SSD.

Put into other words: If I take an NVMe SSD out of storage and plug it into a system or USB enclosure, then apply power, can I remove power after a few seconds or do I need to leave it plugged in for several hours to complete a refresh?

DigitalGoat · Jul 27, 2022

@hsehestedt, I believe my post, 4th one down, should answer that very question. :)

hsehestedt · Jul 27, 2022

DigitalGoat said:
@hsehestedt, I believe my post, 4th one down, should answer that very question. :)

I appreciate the pointer, and had in fact seen that article previously, but it DOES NOT answer my question. It answers questions related to how long an SSD can retain data when powered off. Once again, I don't care about that. I simply want to know how long I need to leave it plugged in with power applied to refresh the charge on each cell.

I realize that my original post may not have made that as clear as I would have liked, but the answer to that question is my goal

.

DigitalGoat · Jul 27, 2022

I don't think SSD data retention works the way you think, the cells do not need power to retain the charge, hence non volatile RAM, so just re applying power will not 'refresh' the data held in the cells.
Any leakage (and therefore data corruption) over time would remain the same even with a fresh application of power.
You need to refresh the data held, for example by copying the data off the device, then copying it back to the device, or formatting the device and copying the original data from the source to the device as a fresh copy.
So the answer becomes 'as long as it takes to re write the data to the device' if that makes sense.

Fabler2 · Jul 27, 2022

hsehestedt said:
I appreciate the pointer, and had in fact seen that article previously, but it DOES NOT answer my question. It answers questions related to how long an SSD can retain data when powered off. Once again, I don't care about that. I simply want to know how long I need to leave it plugged in with power applied to refresh the charge on each cell.

I realize that my original post may not have made that as clear as I would have liked, but the answer to that question is my goal :).

This is an interesting thread

and found this,

SSDs can lose data if powered off for a long time. Just powering them on (don't have to access every file) will recharge the cells. But h...

Answer (1 of 5): Thanks for A2A. SSDs can lose data if powered off for a long time. Just powering them on (don't have to access every file) will recharge the cells. But how long does it take an SSD to recharge everything (seconds, minutes, hours)? The idea of recharge is a complete myth. The o...

www.quora.com

SIW2 · Jul 27, 2022

You need to refresh the data held

That is what the DiskFresh program is for. I dont know how frequently it should be done. If I had data stored on an hd for the long term, I would probably run diskfresh on it every few years.

refresh your hard disk signal without changing its data by reading and writing each sector and hence making your disk more reliable for storage.

Whether it is better to do it every couple of years or every five years, I dont know,.

DiskFresh - Refresh Hard Disk Signal

Bree · Jul 27, 2022

hsehestedt said:
I was simply curious whether the electrical charge gets recharged immediately when the SSD is connected to a source of power

DigitalGoat said:
I don't think SSD data retention works the way you think, the cells do not need power to retain the charge, hence non volatile RAM, so just re applying power will not 'refresh' the data held in the cells.

I agree with DigitalGoat. It appears from the article in DigitalGoat's link that applying power will considerably slow down the loss of charge from the cells, but does nothing to refresh it. Note also that it states the '1 year at 30°C' expected retention is the mininmum for an SSD that has been worn beyond its TBW designed endurance. A fresh new SSD should be better at retaining charge in its cells while un-powered, quoting 10 years as typical.

Remember that the figures presented here are for a drive that has already passed its endurance rating, so for new drives the data retention is considerably higher, typically over ten years for MLC NAND based SSDs. If you buy a drive today and stash it away, the drive itself will become totally obsolete quicker than it will lose its data.

DigitalGoat · Jul 27, 2022

Also there are other factors as to how long an SSD will retain data, such as quality of components, scale of process and voltage needed to change state.
Add to those factors the number of erase/ write cycles per cell and over what time period plus operating temperatures and storage temperatures and the question of data retention time becomes 'best guess' based on a device adhering to the JEDEC specifications.
The OP's question was about how long to power on a device to refresh the data, however the question how often should I refresh my data is actually much more relevant as simply powering the device will not refresh the data.

iko22 · Jul 27, 2022

This could be the myth-buster everyone is searching for ...

Our results strongly suggest that appropriate read cycling could be an effective way to retrieve threshold voltage (V-th ) down-shifts during data retention.

Source: Impacts of Lateral Charge Migration on Data Retention and Read Disturb in 3D Charge-trap NAND Flash Memory | 2020 IEEE 15th International Conference (ICSICT) | ieeeexplore.

bobkn · Jul 27, 2022

hsehestedt said:
My apologies to all. I may have given the wrong impression with my initial post.

I was not attempting to solicit comments on alternate forms of media to which I might consider backing up.

I already have strategies that include roughly 150 TB of HDDs and 4 TB of Blu-Ray media (that's a lot of Blu-Rays), the SSDs will serve a different purpose where extremely rapid access will be needed.

My research just led me to wondering exactly what needs to be done to "refresh" the electrical charge on an SSD. Since there is a limited amount of time that data can be retained on an SSD, be that 1 week, 1 year, 10 years, whatever, that's not even my main concern. I was simply curious whether the electrical charge gets recharged immediately when the SSD is connected to a source of power or whether the cells electrical charge only get refreshed as the controller performs its maintenance tasks and "touches" every cell on the SSD.

Put into other words: If I take an NVMe SSD out of storage and plug it into a system or USB enclosure, then apply power, can I remove power after a few seconds or do I need to leave it plugged in for several hours to complete a refresh?

We know. Thread drift.

A quick online search suggests that data retention for a powered-on SSD may be very long, depending on its controller. Some may auto-refresh. Presumably applying power at long intervals will run the refresh cycle.

hsehestedt · Jul 27, 2022

Bree said:
I agree with DigitalGoat. It appears from the article in DigitalGoat's link that applying power will considerably slow down the loss of charge from the cells, but does nothing to refresh it. Note also that it states the '1 year at 30°C' expected retention is the mininmum for an SSD that has been worn beyond its TBW designed endurance. A fresh new SSD should be better at retaining charge in its cells while un-powered, quoting 10 years as typical.

So, let me clarify, because there seems to be some general confusion as what I am asking.

Suppose that buy a battery. That battery will have a shelf life. After x number of years, the battery will no longer be good because it very slowly over time depletes it's charge even though it is not connected to anything that draws power. This effect is known as "self discharge".

In very broad terms, an SSD works much the same. When you "write" data to an SSD you are placing a very tiny charge on memory cells. That's simply how an SSD stores data. The level of that charge can then later be read back to determine the contents of that memory cell. Over time, that charge will dissipate. Normally, this is not an issue so long as power is applied to the SSD on occasion.

My question was simply this: How long does power need to be applied to refresh all the data? Does it happen instantly when power is applied or does this happen only slowly over time as the controller performs tasks in the background?

Anyway, I have inquires in to some of the SSD manufacturers regarding this now.