Question Should I return a new SD card with only a few bad sectors?

Jul 28, 2021
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Today I went to the store and bought the cheapest 128GB micro SD card I could find as storage for my Raspberry Pi 4 model B. When I came home I ran one write and one read test using f3 which revealed 9 Megabytes of bad sectors, a log file containing f3write and f3read logs can be found here.
The card in question is a 128 Gigabytes large Müller (own brand) Class 10 microSDXC card that cost me 23€ and came with a 5-year warranty even though I could not find any information on the card online.

So should I just try to use the card and hope for the best or should I try to return the card and buy another one from a trusted manufacturer?
And do new SD cards usually have a small amount of bad sectors or did I just have some bad luck with this one?
 

Bazzy 505

Proper
Jul 17, 2021
249
82
170
4
Today I went to the store and bought the cheapest 128GB micro SD card I could find as storage for my Raspberry Pi 4 model B. When I came home I ran one write and one read test using f3 which revealed 9 Megabytes of bad sectors, a log file containing f3write and f3read logs can be found here.
The card in question is a 128 Gigabytes large Müller (own brand) Class 10 microSDXC card that cost me 23€ and came with a 5-year warranty even though I could not find any information on the card online.

So should I just try to use the card and hope for the best or should I try to return the card and buy another one from a trusted manufacturer?
And do new SD cards usually have a small amount of bad sectors or did I just have some bad luck with this one?

that's definately a faulty SD crap, return it if you can.

At prices micro SD's run for these days, there's little reason to cheapen up.
Buy one from a reputable brand like Samsung, SanDisk or Kingston and you won't have to deal with such problems.
 
Reactions: Abstraction Mage
Jul 28, 2021
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10
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Many thanks to you all for your advice, however my situation has changed a bit: I have run two more memory tests, one using h2testw and another one using f3, both of which reported no bad sectors whatsoever. Results of the h2testw test are here (in German, second line translates to 'finished with no errors') and console logs of the second f3 test can be found here.

Comparing the logs of the two f3 tests it seems like all the previously bad sectors are now good sectors again - I am confused as to why something like this can happen and unsure if I should still demand a replacement card if the one I have seems to be working fine now.

I would greatly appreciate any technical information on regarding this occurrence as well as further advice.
 

Bazzy 505

Proper
Jul 17, 2021
249
82
170
4
Many thanks to you all for your advice, however my situation has changed a bit: I have run two more memory tests, one using h2testw and another one using f3, both of which reported no bad sectors whatsoever. Results of the h2testw test are here (in German, second line translates to 'finished with no errors') and console logs of the second f3 test can be found here.

Comparing the logs of the two f3 tests it seems like all the previously bad sectors are now good sectors again - I am confused as to why something like this can happen and unsure if I should still demand a replacement card if the one I have seems to be working fine now.

I would greatly appreciate any technical information on regarding this occurrence as well as further advice.
This typically caused by what is called "read disturb". Basically when a cell is being read, it can change the state of a nearby cell. To a certain extent this happens in all NAND memory, and controller's error correction routines compensate for this. However if too many of such errors happen within a particular cell block, controller can no longer compensate and you will have the experience you had.

Now the difference between a decent controller with decent grade nand chip and <Mod Edit> one is, that on good one, you will never see this behavior within useful live of the card. With a <Mod Edit> one you will have to deal with it right out of box.
 
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Reactions: Abstraction Mage

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