Reverse-engineering and analysis of SanDisk High Endurance microSDXC card (2020)

Re:Reverse-engineering and analysis of SanDisk High Enduranc... by dehrmann on Sunday February 02, 2025 @04:59PM (#42912264)

I back up important things on SLC USB-A flash drives and write refreshed copies at least annually. The drives are small (<=8GB), expensive, there are only a handful of manufacturers (mine's an ATP), and you're probably ordering it from Digikey or Mouser. SLC will supposedly hold data at rest longer, and USB-A means I can find readers for at least another decade. We'll see if retention at rest is actually good.

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Re:Reverse-engineering and analysis of SanDisk High Enduranc... by userbinator on Sunday February 02, 2025 @05:16PM (#42912418)

You can get (real!) SLC USB drives from Aliexpress too, for around $0.70/GB. These aren't the ultra-cheap ones which are often fake in capacity, but prominently advertise the type of flash and controller they use.

I also have some really small USB drives from around 2 decades ago, of course SLC flash (the only type of NAND flash at the time), and can confirm that their data is still intact. They've gone through probably a few dozen full-drive writes, while SLC flash back then was rated for 10 years retention after 100K cycles.

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Re:Reverse-engineering and analysis of SanDisk High Enduranc... by pdimitar on Sunday February 02, 2025 @06:06PM (#42912823)

Yeah, I have 2 such from AliE and they perform well and haven't lost anything yet even though they have dozens of thousands of files at rest that are updated 1-2 times a month, for almost 3 years now. Quite pleased with them.

They are indeed more expensive but nothing that a programmer salary would notice even if you bought 10 of them. I am wondering whether I should buy another pair and use it as a metadata mirrored vdev on my media NAS. Haven't decided yet.

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Re:Reverse-engineering and analysis of SanDisk High Enduranc... by dehrmann on Sunday February 02, 2025 @07:12PM (#42913288)

> I am wondering whether I should buy another pair and use it as a metadata mirrored vdev on my media NAS. Haven't decided yet.

Probably not worth the operational overhead, and in the past, I remember USB having significantly worse write latency than SATA.

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Re:Reverse-engineering and analysis of SanDisk High Enduranc... by pdimitar on Sunday February 02, 2025 @08:00PM (#42913696)

Yeah, thought the same. Not to mention that I tried to have a bunch of old USB sticks put into one of my servers and it added like two minutes to its reboot time. (Though admittedly I didn't fight hard with systemd to make sure their mounting does not block anything -- it's likely possible to do.)

Ultimately I am not willing to shell out hundreds of EUR for f.ex. 2x SLC internal SSDs at 32 or 64 GB each so I guess I'll just have a few spare disks around when I am back to being employed, and that's going to be that.

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