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Unpowered SSDs slowly lose data

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Re: Unpowered SSDs slowly lose data

#21

Post by ggm »

gosub100 wrote: post #13
paulkrush wrote: post #2

I had to search around and feel like a dork not knowing this. I have my data backed up, but I keep the SSDs because it's nice to have the OS running like it was... I guess I need to be cloning the drives to ISOs and storing on spinning rust.

or you could power them on 1-2x /year.

Power them on and run something to exercise the read function over every bit. Thats why a ZFS filesystem integrity check/scrub is the useful model.

I'm unsure if dd if=/the/disk of=/dev/null does the read function.

Re: Unpowered SSDs slowly lose data

#22

Post by ggm »

loloquwowndueo wrote: post #19
bossyTeacher wrote: post #9

This is why I would rather pay someone a couple of dollars per year to handle all this for me. If need be pay two providers to have a backup.

Who do you pay for this? (To rephrase : which cloud storage vendors do you use?) interested in the $2/month price point :)

tell me about this $2/week filestore option. I'm interested.

Re: Unpowered SSDs slowly lose data

#23

Post by em500 »

sevensor wrote: post #3

Flash is programmed by increasing the probability that electrons will tunnel onto the floating gate and erased by increasing the probability they will tunnel back off. Those probabilities are never zero. Multiply that by time and the number of cells, and the probability you don’t end up with bit errors gets quite low. The difference between slc and mlc is just that mlc has four different program voltages instead of t…

> Honestly I can’t quite believe mlc works at all, let alone qlc. I do wonder why there’s no way to operate qlc as if it were mlc, other than the manufacturer not wanting to allow it.

Manufacturers often do sell such pMLC or pSLC (p = pseudo) cells as "high endurance" flash.

Re: Unpowered SSDs slowly lose data

#24

Post by Yokolos »

joezydeco wrote: post #7
dpoloncsak wrote: post #4

Earlier quoted context omitted.

I could be wrong, but I believe the general consensus is along the lines of "SSDs for in-use data, it's quicker and wants to be powered on often. HDDs for long-term storage, as they don't degrade when not in use nearly as fast as SSDs do.

I've been going through stack of external USB drives with laptop disks in them. They're all failing in some form or another. I'm going to have to migrate it all to a NAS with server-class drives I guess

At the very least, you can usually still get the data off of them. Most SSDs I've encountered with defects failed catastrophically, rendering the data completely inaccessible.

Re: Unpowered SSDs slowly lose data

#25

Post by testartr »

what is the exact protocol to "recharge" an ssd which was offline for months?

do I just plug it in and let the computer on for a few minutes? does it needs to stay on for hours?

do I need to run a special command or TRIM it?

Re: Unpowered SSDs slowly lose data

#26

Post by testartr »

sevensor wrote: post #3

Flash is programmed by increasing the probability that electrons will tunnel onto the floating gate and erased by increasing the probability they will tunnel back off. Those probabilities are never zero. Multiply that by time and the number of cells, and the probability you don’t end up with bit errors gets quite low. The difference between slc and mlc is just that mlc has four different program voltages instead of t…

the market demands mostly higher capacity

tlc/qlc works just fine, it's really difficult to consume the erase cycles unless you really are writing 24/7 to the disk at hundred of megabytes a second

Re: Unpowered SSDs slowly lose data

#27

Post by throw0101a »

traceroute66 wrote: post #15

I assume this blog is a re-hash of the JDEC retention standards[1]. The more interesting thing to note from those standards is that the required retention period differs between "Client" and "Enterprise" category. Enterprise category only has power-off retention requirement of 3 months. Client category has power-off retention requirement of 1 year. Of course there are two sides to every story... Enterprise category s…

> I assume this blog is a re-hash of the JDEC retention standards[1].

Specifically in JEDEC JESD218. (Write endurance in JESD219.)

Re: Unpowered SSDs slowly lose data

#28

Post by PunchyHamster »

testartr wrote: post #25

what is the exact protocol to "recharge" an ssd which was offline for months? do I just plug it in and let the computer on for a few minutes? does it needs to stay on for hours? do I need to run a special command or TRIM it?

I'd imagine full read of the whole device might trigger any self-preservation, but I'd also imagine it's heavily dependent on manufacturer and firmware

Re: Unpowered SSDs slowly lose data

#29

Post by suspended_state »

formerly_proven wrote: post #12
Izkata wrote: post #10

Earlier quoted context omitted.

Huh. I wonder if this is why I'd sometimes get random corruption on my laptop's SSD. I'd reboot after a while and fsck would find issues in random files I haven't touched in a long time.

Unless your setup is a very odd Linux box, fsck will never check the consistency of file contents.

But metadata is data too, right? I guess the next question is, would it be possible for parts of the FS metadata to remain untouched for a time long enough for the SSD data corruption process to occur.

Re: Unpowered SSDs slowly lose data

#30

Post by PunchyHamster »

brian-armstrong wrote: post #14
Izkata wrote: post #10

Earlier quoted context omitted.

Huh. I wonder if this is why I'd sometimes get random corruption on my laptop's SSD. I'd reboot after a while and fsck would find issues in random files I haven't touched in a long time.

It's quite possible. Some SSDs are worse offenders for this than others. I have some Samsung 870 EVOs that lost data the way you described. Samsung knew about the issue and quietly swept it under the rug with a firmware update, but once the data was lost, it was gone for good.

Huh, I thought I got some faulty one, mine died shortly after warranty ended (and had a bunch of media errors before that)
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