Welp, new fear unlocked. I need to move all my backups to ZFS sooner rather than later ...
Unpowered SSDs slowly lose data
131–140 of 341 posts
Re: Unpowered SSDs slowly lose data
#132Earlier quoted context omitted.
Endurance going down is hardly a surprise given that the feature size has gone down too. The same goes for logic and DRAM memory. I suspect that 2035 years time, hardware from 2010 will work, while that from 2020 will be less reliable.
Completely anecdotal, and mostly unrelated, but my NES from 1990 is still going strong. Two PS3’s that I have owned simply broke. CRTs from 1994 and 2002 still going strong. LCD tvs from 2012 and 2022 just went kaput for no reason. Old hardware rocks.
Specifically old Japanese hardware from the 80s and 90s - this stuff is bulletproof
Re: Unpowered SSDs slowly lose data
#133One key point about retention which is not often mentioned, and indeed neither does this article, is that retention is inversely proportional to program/erase cycles and decreases exponentially with increasing temperature. Hence why retention specs are usually X amount of time after Y cycles at Z temperature. Even a QLC SSD that has only been written to once, and kept in a freezer at -40, may hold data for several de…
I also seem to remember reading retention is proportional to temperature at time of write. Ie, best case scenario = write data when drive is hot, and store in freezer. Would be happy if someone can confirm or deny this.
I know we're talking theoretical optimums here, but: don't put your SSDs in the freezer. Water ingress because of condensation will kill your data much quicker than NAND bit rot at room temperature.
Re: Unpowered SSDs slowly lose data
#134what 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?
If you are using a backup program like "kopia" there are special commands to recheck all hash blocks.
You just can't trust the hardware to know how to do this, need backup software with multiple backup locations, it will know how to recheck integrity
Re: Unpowered SSDs slowly lose data
#135Earlier quoted context omitted.
I also seem to remember reading retention is proportional to temperature at time of write. Ie, best case scenario = write data when drive is hot, and store in freezer. Would be happy if someone can confirm or deny this.
I know we're talking theoretical optimums here, but: don't put your SSDs in the freezer. Water ingress because of condensation will kill your data much quicker than NAND bit rot at room temperature.
What about magnetic tape?
Re: Unpowered SSDs slowly lose data
#136Earlier quoted context omitted.
SSD firmware engineer here. I work on enterprise stuff, so ymmv on consumer grade internals. Generally, the data refresh will all happen in the background when the system is powered (depending on the power state). Performance is probably throttled during those operations, so you just see a slightly slower copy while this is happening behind the scenes. The unused space decaying is probably not an issue, since the int…
So say I have a 4TB USB SSD from a few years ago, that's been sitting unpowered in a drawer most of that time. How long would it need to be powered on (ballpark) for the full disk refresh to complete? Assume fully idle. (As a note: I do have a 4TB USB SSD which did sit in a drawer without being touched for a couple of years. The data was all fine when I plugged it back in. Of course, this was a new drive with very lo…
More certain to just do a full read of the drive to force error correction and updating of any weakening data.
Re: Unpowered SSDs slowly lose data
#137[dead]
Re: Unpowered SSDs slowly lose data
#138Earlier quoted context omitted.
Completely anecdotal, and mostly unrelated, but my NES from 1990 is still going strong. Two PS3’s that I have owned simply broke. CRTs from 1994 and 2002 still going strong. LCD tvs from 2012 and 2022 just went kaput for no reason. Old hardware rocks.
Specifically old Japanese hardware from the 80s and 90s - this stuff is bulletproof
I still have a Marantz amp from the 80's that works like new, it hasn't even been recapped.
Re: Unpowered SSDs slowly lose data
#139Earlier quoted context omitted.
I know we're talking theoretical optimums here, but: don't put your SSDs in the freezer. Water ingress because of condensation will kill your data much quicker than NAND bit rot at room temperature.
What about magnetic tape?
For long term storage? Sure, everybody does it. In the freezer? Better don't, for the same reason.
There are ways to keep water out of frozen/re-frozen items, of course, but if you mess up you have water everywhere.
Re: Unpowered SSDs slowly lose data
#140A solution I haven't yet seen in this thread is to buy multiple drives, and sacrifice the capacity of one of those drives to maintain single parity via a raidz1 configuration with zfs. (raidz2 or raidz3 are likely better, as you can guard against full drive failures as well, but you'd need to increase the number of drives' capacity that you're using for parity.) zfs in these filesystem-specific parity-raid implementa…
How would this work? Wouldn't all these drives start loosing data at roughly at the same time?
Yes, but different pieces of data. The stored parity allows you to reconstruct any piece of data as long as it is only lost on one of the drives (in the single parity scenario).
The odds of losing the same piece of data on multiple drives is much lower than losing any piece of data at all.