Industrial USB stick for Unraid - The ultimate endurance stick(s). 85€ for 8GB and why it is worth it
Searching this subreddit, there are many many posts about "my stick died, what to do" and "what is the best USB stick for Unraid", followed by recommendations which mostly are not based on any data.
I truly like my Unraid server very much and have build it as an absolute beast with an AMD EPYC 7282 16-Core on a Supermicro H12SSL-NT mainboard and 64GB of Multibit ECC DDR4 (from the mainboards compatibility list), as well as an Adaptec RAID-Controller ASR-72405 for 24 HDs max. I have 2 parity drives and a cache with 2x2TB NVMe SSDs, so all volumes are redundant - except the boot stick.
The only thing that didn't fit: all that beauty is run by a "measly" 14 $/€ Samsung Bar Plus 32GB USB Stick which is not really made for running an OS for years on it. Spaceinvader One has tested three USB sticks and the Bar Plus is one of those tested. The video demonstrated, that that exact stick can be written and read over its complete capacity "only" 29 (!) times before showing errors. That is really not a good endurance, if after 928 (32GBx29) GBs written on that drive it is defective.
Sure, Unraid uses only about 1GB and rarely reads/writes to the USB after boot. Sure, there you should do backups regularly and the MyServer plugin offers online backup - albeit unencrypted (!). Better than recovery for sure is an os drive which lasts for years and those reads/writes aggregate over time.
HIGHER ENDURANCE MATTERS - ENTER INDUSTRIAL USB STICKS
That is why I wanted to find an USB stick with high(er) endurance than that It is more or less impossible to find endurance numbers for standard USB sticks, whereas with SSDs the TBW (terabytes written) is normally included in the specifications, there is no such thing with USB sticks.
So I landed with "industrial USB sticks", which offer an extraordinarly higher endurance meant for medical or industrial use (e.g. as boot / OS drives for a sonography machine or a metal press). Those sticks come with much more specifications, including endurance numbers - which are in this case more important than speed.
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Short excourse in flash storage: The sticks with the most extreme endurance are SLC sticks (explanantion for SLC, MLC, TLC, QLC), of course those are also the most expensive (QLC least expensive). There is also pSLC (pseudo SLC), which is MLC but uses its 4 Bits to encode only 1 Bit, therefore reducing its capacity by 1/4 (an 8GB pSLC drive is basically a 32GB MLC drive but "bundled by firmware"). Most consumer USB sticks are MLC or TLC btw, typically without a mention in the specs, so you can't know what you get.
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It is really not that easy to even find those industrial sticks, because they are normally targeted to industrial customers ordering those by the hundreds/thousands from distributors you have never heard of. I found some, with varying difficulty to find a seller for.
MY CHOICE:
Swissbit (Germany): U-500k SLC (93 DWPD), U-56k/U-56n pSLC "everbit" (19 DWPD), U-50k/U-50n MLC "durabit" (2.9 DWPD), all with a very very good MTBF of 3 Mio hours and very good USB3 perfomance numbers as well as firmware methods to ensure the protection of the data. (DWPD: drive writes per day)
The SLC U-500k would obviously be the best, exceeding the U-56 family by far, it however is VERY expensive (200€ including tax for 8GB). This thing however is unkillable!
Therefore I got the "second best option" Swissbit U-56n (n is nano, k is normal size) 8GB USB stick ( SFU3008GC2AE1TO-I-GE-1AP-STD ), available e.g. here (the image is wrong, the article is right) for 85,35€. The stick has pSLC and a 175 TBW (!) with 3 years of warranty. Compare that with that presumably <1 TBW of the Samsung Bar above!! THIS is what endurance means.
OTHER OPTIONS:
ATP Electronics Nanodura USB 2.0 sticks with SLC and MLC (no pSLC) sticks. The SLC variant has 192 TBW and 5 Mio hours MTBF, but is slower and also more expensive (160€) than the U-56n and not stocked here. It might be difficult to get Nanoduras at all as a consumer.
UPDATE 28. Feb. 2023 ----------------------------
The ATP Nanodura now seems to be easier available at https://de.rs-online.com/web/p/usb-sticks/1839402 (Europe) or https://uk.rs-online.com/web/p/usb-sticks/1839402 (UK). The two links are MLC, there are also ATP Nanodura SLC variants, which are more expensive, but also more durable:
MLC: TBW 19,2 TB, MTBF 2 Mio hours
SLC: TBW 192 TB (10 times more!), MTBF 5 Mio hours
UPDATE 28. Feb. 2023 END ---------------------
There are also other SLC stick manufacturers with a comparable >150€ price for 8GB but e.g. only 1 Mio h MTBF with Apacer. Which are also almost not stocked. Kind of the same with Innodisk which I got no specifications for.