microSD card specifications

[mbetel]

Are there guidelines as to which microSD card should or can be used e.g. class, size?

[johannes]

I haven't seen a microSD card that did not work, but I have not seen any anyone testing bigger that 32GB cards.

Cards should be FAT formatted and only DOS-style 8.3 filenames are supported. Longer filenames always have an abbreviated name.

For performance, there is huge speed difference between cards, and most important, the speed rating is hardly relevant.
The speed rating (Class-4, Class-5, Class-10, UHS-I, UHS-II) are marketing numbers and characterize performance for long contiguous read and write operations. While in Axoloti small buffer read and writes are far more relevant.
I have seen Class-4 cards perform well, and I have seen UHS-I cards perform less stellar.

The UHS-I and UHS-II specs are not used, but those cards are backwards compatible.

This site has some detailed benchmarks, most relevant are the "Random Read, 4 KB (QD=1)" and "Random Write, 4 KB (QD=1)"
http://www.tomshardware.com/charts/microsd-cards-2014/benchmarks,169.html

The "sdbenchmark" object in Axoloti runs similar benchmarks also including smaller buffer sizes. Put it in an empty patch, launch the patch, and it will print the results in the log.

[AdrianWillaert]

Thanks for the specs about the microSD.
Is it possibile to format the microSD directly via the Axoloti software
or it's necessary to do it with a computer?

Thanks

[W_T]

Is there perhaps a 'best buy' tip for buying an micro sd card for the Axoloti at this moment.
brand, speed and or how manny gb max?

thanks

[keyman]

@W_T this might help:

SDCard Benchmarks

Continuing the discussion from Uploading to SD as startup vs internal Flash: We have had a couple of post recently about using SD card, and their performance. I thought it might be interesting to have a topic where can collect users experiences about different cards and their performance. please post in this topic information about the cards you are using and their performance: (please only post this info into this topic, any other discussion about failures/poor performance in a separate …

[W_T]

thank you very much keyman

[keyman]

Thanks @SirSickSik you can upload a description/benchmark to this thread

SDCard Benchmarks

Continuing the discussion from Uploading to SD as startup vs internal Flash: We have had a couple of post recently about using SD card, and their performance. I thought it might be interesting to have a topic where can collect users experiences about different cards and their performance. please post in this topic information about the cards you are using and their performance: (please only post this info into this topic, any other discussion about failures/poor performance in a separate …

[mcpepe]

I buyed a new 64GB last week and it is formated in ExFat format.

Can I use it with Axoloti?

[keyman]

Well if you have it and want to use it with Axoloti better format using Axoloti

SDCard Benchmarks

Continuing the discussion from Uploading to SD as startup vs internal Flash: We have had a couple of post recently about using SD card, and their performance. I thought it might be interesting to have a topic where can collect users experiences about different cards and their performance. please post in this topic information about the cards you are using and their performance: (please only post this info into this topic, any other discussion about failures/poor performance in a separate …

Format the card in Axoloti
important for consistency, do NOT rely on formatting from PC/Mac or manufacturer
Window/Remote
use arrows to go to SDCard tools
use arrows to go to Format
press Enter
(a bug means that the card will be disconnected with a timeout BUT it will still be formatted, so just connect again)

[johannes]

I've heard positive reports using 64GB cards, but haven't tried myself. ExFAT is not supported, but reformatting to FAT32 should be fine.

[SirSickSik]

oeh, I just saw a nice card coming by.. 128GB and a writing speed of 90MB/S
on paper that's faster then my current one
samsung microSD 128GB

[timeorspace]

? could not find this ability to format from the Axoloti

[thetechnobear]

There's now an object to do this
util/format

[Janko]

For future reference sake I am looking to find a fast 32gb MicroSD for Axoloti and found this article useful
https://www.jeffgeerling.com/blog/2019/raspberry-pi-microsd-card-performance-comparison-2019

To summarise most high performance cards are optimised for moving large files quickly and not for random 4k I/O, which seems to be what we are after: "But when you look at random 4K I/O (which is 4 kilobyte blocks of data, written to random segments of the flash drive), the performance is vastly reduced. Instead of seeing the "95 MB/sec" that's advertised on the front of the Sony microSD card, for example, I found 0.66 MB/s write speed when writing random 4K blocks."

According to the authors benchmarks as of 2019 the best card for the Rasberry Pi (and likely the Axoloti by extension) is the Samsung 32GB EVO Plus Class 10 Micro SDHC, which luckily is quite cheap at $12 AUD