SD/MMC cards, a year later (2010)

http://lists.laptop.org/pipermail/devel/2010-August/029503.html

by userbinator • 2 years ago

13 18 2 years ago

lists.laptop.org

I’m looking into using sd cards for my backups. Easy to transport， easy to store elsewhere, not a challenging write-erase workload. Does anyone have experience with this or have recent measurements? I do see many of the problems mentioned in the article below.

gritzko2• 2 years ago

Funnily enough, I am doing these experiments in 2024. All seems to work in the short run. Please wait a year for the results :)

P.S. USB flash drives failed miserably, except for maybe Samsung FIT. Very unreliable.

dogsledsleddog• 2 years ago

USB flash failed in terms of writes? I'm kind of curious about the story of longterm offline storage, vs occasional use since I think the controller needs to both have logic to actively refresh over months/years and occasionally be on to do so?

st_goliath3• 2 years ago

I’m looking into using sd cards for my backups.

probably not a good idea. Modern, high density SD cards will likely use not very reliable MLC NAND internally, pretty much requiring active maintenance by the software on the built-in controller.

I once had an embedded board booting from MLC NAND that lost its entire u-boot environment after being without power for a year, just sitting on a shelf in my office.

Similarly, at home, I have an SSD with Windows on it for occasionally playing games. It required extensive recovery after sitting in a desk drawer for a little over a year.

I generally wouldn't really trust flash memory for offline backups.

teddyh• 2 years ago

Unpowered – i.e. unplugged – flash or solid state memory have been shown to lose its data after three months: <https://news.ycombinator.com/item?id=37144598>

userbinator2• 2 years ago

You might be referring to "MLC" in the generic sense of multiple bits per cell, but SD cards are more likely to be TLC or QLC these days (and there may even be some PLC appearing now), 3 or 4 bits per cell rather than the original meaning of MLC for 2-bit MLC.

My experience with old (as in ~2008-2009) 2-bit MLC NAND, with not much wear, has been that they've been OK for over a decade. Ditto for some early SLC USB drives (the biggest being 512MB).

michaelt• 2 years ago

In my experience, Raspberry Pi DIYers are more than happy to talk about their experiences, but they've only got small sample sizes, they're buying things at retail, some will be relatively price-insensitive, and people who have problems might be particularly eager to complain.

These people hate SD cards with a passion.

The kind of people who are in a position to report on failure rates across a fleet of hundreds of SD cards (a) don't always have their employer's permission to talk about it, (b) don't want to publicly bitch about vendors they want to maintain a good relationship with, (c) can be very price sensitive depending on the product and (d) are often buying through special channels where vendors will do things like guarantee a specific controller firmware version.

These people keep on releasing products that use SD cards.

Modified30192• 2 years ago

While not quite as tiny, an nvme enclosure with a real drive is likely going to be more reliable, assuming the USB port it’s connected to can actually supply the power it needs.

The enclosures I’m currently fond of are from dockcase, which have a capacitor (PLP meaning power loss protection), so if power is cut, the drive is sent a “oh shit make things safe now” signal and has a few seconds to do so.

I use the larger versions, but there’s a 2230 sized one https://www.dockcase.com/products/dockcase-pocket-m2-nvme-sm...

That said, expect all drives to fail. Some you get a warning, others you don’t, so have multiple backups. I don’t recommend the cheap vendor branded Samsung SSDs on eBay, had too many of those die with the firmware version reporting as “ERRMOD” (error mode).

Another good thing to note, is how to power cycle SSDs. Outside of Samsung drives, this has worked on a few drives over the years that decided to suddenly stop working: https://dfarq.homeip.net/fix-dead-ssd/

Adachi91• 2 years ago

SD cards have always boggled me as a storage medium and I've personally only ever used them on Pis and other SBCs, it seemed like the more expensive ones my brother would purchase would die fairly fast on the PI's I was maintaining for him. On the other hand I have a tinker board (gen 1) that has used the same SD[0] since 2017 that is currently running Bind9, Nginx, Prometheus, Grafana, Matrix synapse home server, and several go projects I've made that use a mix of either postgresql or MySQL. While each year my anxiety raises about it dying, it seems to be running fine still at around 89% utilization. Not sure if it is just built different or I hit jackpot bin of SD cards, either way I've been looking for an SBC upgrade that uses either pcie NVMe or has SATA capabilities for an actual HDD so that I don't have to worry about it as much. Even if it did die today everything on it is backed up to my PC.

[0] https://www.amazon.com/Samsung-MicroSDHC-Adapter-MB-ME32GA-A...

reginald78• 2 years ago

I've heard it suggested that Raspberry Pis are typically run on terrible quality power supplies which contribute to SD cards being corrupted at a much higher rate than if they were using in a PC or mobile phone that has more stable power.

SD/MMC cards, a year later (2010)

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