Permanence of data on Un-powered SSD?

Flizard

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Oct 3, 2012
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Hello, I don't think I have ever come across information on the permanence of data residing on a SSD storage unit that is permenantly powered down?
While in use data is continually being rewritten by garbage collection and 99.99% of computers are powered up every day. For example, what if the computer becomes part of an estate where no one perhaps 'attaches' to a machine for months or longer... just an example.
 

CaedenV

Splendid
when a computer is 'powered down' it still receives a little bit of power for some things, and should be fine. Being unplugged from the wall is an entirely other issue which can potentially cause issue.

@alvine
SSDs are like flash drives, but flash drives have memory that is harder to change, which is why they are slow, but also why they are unaffected by long times without any active power. But you leave a flash drive unplugged long enough (~1 year or so) and you will get some corruption or data loss. SSDs will corrupt over time, and from what I have read they should be fine unpowered for at least 2-3 months, and could be fine for several months (6-12 months), but they do need a little bit of power over time to maintain that data integrity.

But even if it is a device that you only use once a month or so, it should be enough power to keep anything bad from happening.



I think the bigger question is why on earth you would spend the money on an SSD for a device that you never use?
 

CaedenV

Splendid
when a computer is 'powered down' it still receives a little bit of power for some things, and should be fine. Being unplugged from the wall is an entirely other issue which can potentially cause issue.

@alvine
SSDs are like flash drives, but flash drives have memory that is harder to change, which is why they are slow, but also why they are unaffected by long times without any active power. But you leave a flash drive unplugged long enough (~1 year or so) and you will get some corruption or data loss. SSDs will corrupt over time, and from what I have read they should be fine unpowered for at least 2-3 months, and could be fine for several months (6-12 months), but they do need a little bit of power over time to maintain that data integrity.

But even if it is a device that you only use once a month or so, it should be enough power to keep anything bad from happening.



I think the bigger question is why on earth you would spend the money on an SSD for a device that you never use?
 

Flizard

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Hey, I agree and that would be the thought 99.99% of computer owners but there are times when the owner or purchaser (person w emotional attachment and understanding) is not the guardian of the machine. Even looking down the track where an old SSD sits in an old case collecting dust, surplus to needs. That would be in a time when they were a lot cheaper of course...

Storage is such a huge issue, I was just curious. I do some video editing and am looking at SSD's, finding it an interesting and exciting step in computers, but it has limits and specific requirements.

Thanks for the reply :)
 

mavroxur

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I think you may need to brush up on flash memory facts. While flash memory may corrupt over time, I promise, the timeframe you mention is much much shorter than the actual timeframe. The only negative effect to having a computer unplugged for an extended period of time may be a dead CMOS battery, but the SSD should be just fine.
 

CaedenV

Splendid

Ya, they are awesome for video editing! I now use a portion of my SSDs as my 'active project' drive, and it is unbelievable performance compared to my old HDDs. Still I would not trust my SSDs for long term storage, and will continue to use my HDDs for such things. But for fast 'glorified temp storage' you simply cannot beat an SSD.

Also, even if an SSD were to sit for years and corrupt your data, you would still be able to plug it in and use it again down the road. Just don't trust that your data would still be there after sitting so long.

@mavroxur
I could very well be wrong on the time length. I do know that I have had corruption happen in under a year on a flash drive (lost one in the couch for ~10 months lol). I also remember reading about unplugging an SSD can cause corruption in under a year when I did my research before buying my first SSD a little over a year ago. Forgive me for not citing a specific article as I was reading a lot of stuff from a lot of sites at the time and it was over a year ago, but I do remember reading about it on a few sites. I guess you could say that my brain is about as corruptable as an SSD in that regard :p

At any rate, I think we could all agree that an SSD is not an archival medium like CD/DVD/HDDs can be, but they work perfectly fine under even occasional use situations.
 

Flizard

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That's what it's all about, not the media but the data. Some of it is more precious than other, very little of it truly vital. A movie perhaps, the long missing but highly prized masters of a famous rock group or rendition of a greek play or just the doodles of a budding creative artist. Not always sterile office records saved game levels. ;)

I was looking at the Samsung '840 PRO' earlier, it seems an Xtreemly capable SSD! It's lesser version the '840' is TLC (Triple level cell) instead of the almost default MLC nand available mostly in the consumer market. I suppose it's like raid 0 at the bit level and perhaps comes with equal risk/reward equation.

Solid State seems so durable and neat n tidy but as you say, it is no archival medium like CD/DVD/HDD or Blu-Ray, Tape or the Cloud. But I am looking forward to experiencing some super fast reads!
 

nukemaster

Titan
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They have TLC out do they? Its just another MLC(Multi Level Cell)

As I understand it, TLC(sure I will call it that :) ) is designed with reduction in cost in mind.

The problem is how you have to write 3 bits to each cell to fill it meaning that if a cell has 1 bit written, when you want to add more, you have to erase the cell(the thing the causes NAND to wear overtime) and rewrite the old data + the new 1 or 2 bits.

Some may say it will wear out faster. I am not sure, it is very rare to write single bit data.

Either way, that is the reason SLC was so expensive. Each cell only holds one bit, but it has the advantage of never having to rewrite that cell do add to it. That makes SLC very durable(it has to be erased less).

The need to program erase cells is also the reason why some SSD's when full or abused, have a performance hit. They are program erasing half full cells to fit new data in.

Back on topic. I too will not use a SSD for permanent storage. I was always of the impression that they SSD's had at least one year of data retention, but I have not left one out of a system un-powered for that kind of time.

I am sure i have left SD cards un-powered for that kind of time in the past.
 
For SSDs, Dell's response to a simular question:
6. I have unplugged my SSD drive and put it into storage. How long can I expect the drive to retain my data without needing to plug the drive back in?
It depends on the how much the flash has been used (P/E cycle used), type of flash, and storage temperature. In MLC and SLC, this can be as low as 3 months and best case can be more than 10 years. The retention is highly dependent on temperature and workload.
NAND Technology
Data Retention @ rated P/E cycle
SLC ... 6 Months
eMLC .. 3 months
MLC .. 3 Months

have seen reponse to this quest that suggest 10Years for SLC and 8 Months to 1 yr for MLC. But Highly dependent on Temperature, die size of nand, and quality of NAND chips.

On other media.
CDs very good, have some cds over ten yers old that still work.
DVDs commercial ons seam to be quite Long, But the Garden varity DVD write once and DVD =/- R can be very short. There are several posts that indicat movies stored (not the commersial version) data degregation can occure in as little as 6 months. HIGHY dependent on temperature/RH. For Long term Data retention use Class M DVD disk - NOT not all DVD writers are certified for Class m writes.

HDD. Biggest problem here is magnetic domain migration. This is when the domain is opposite the domain next to it. Like putting to magnet next to one another. Newer platters have gone to perpendicular domains, and are "packed" at a much higer density. Just not sure how long, but over time the data on magnetic platters also become unreliable. Newer HDDs may be shorter than the "older" HDDs. Had some OLD SCSI 2 gig High end drives that were stored for 4 years, some survived, some didn't. Most here do NOT normally stich a HDD up for 4 to 5 years and then retrive data from the HDD.
 

Flizard

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yes agreed TLC is by definition still MLC :na:

The reward of raid 0 being performance and the reward of TLC is cost and miniaturization or density, however the risk is not so clear as it is with raid 0. If garbage collection and trim are working there is good likelihood there will be free pages enough to fit the new version of the data but not trigger trim because the pages still is being used by recycle bin. . ...

I guess at the end of the day, having more data per nand chip will mean more accesses and more writes to the cells and with the internal circuits getting finer finer, the durability takes a hit. Risk equals durability.

Perhaps with smaller structure would come an acceleration in data corruption from a powered down state? It is a matter of migrating electrons I believe? Perhaps your 12 months might be 9 months for the TLC nand?
 

nukemaster

Titan
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m-disc?

http://millenniata.com/m-disc/

I have lots of old drives from years back and they seem to hold data ok.

But ouch on the 3 month time.

I would load up my old Kingston V series drive with data then store it for a year to see what it does, But I would want to use it for something so I doubt it would get stored long term. But for science!!
 

Flizard

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So potentially, as CaedenV said, it might be a matter of a few months! Ofcourse as the amount of data increases, the chance of the corruption being critical or terminal in nature will increase.

I heard it said that when one member of a mirrored raid fails, there is a 'real' increase in the likelihood of another member of the array to fail within an hour of the first failure. It is a strange and mysterious sector of the storage world from the humble home PC to the mega factory sized data centers.
 

dkarl49406

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Actually, the SSD can lose data if it is unplugged for a long time. e.g. 2 years. The leakage of the chips is low, but eventually the states will change due to internal leakage. this will cause permanent losss of data and result in the computer not being able to start back up.
 

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