On a side note: are there any really reliable MicroSD cards? The only info I found on the Internet in this regard is that they are mostly manufactured from low-quality memory chips (sometimes even scavenged from god-knows-where) which is hidden by a built-in memory controller with a clever (or not so clever) algorithm.
Even considering all the troubles I met with such setup, it is still tempting to have some additional swap if there is an SSD-quality MicroSD card…
I have also just read the description of commit in which ZRAM (and swap in general) is tuned, and that’s impressive. Are these configurations necessarily system-wide, or may be configured for different swaps separately?
We learned a while back that the sdcard reader in the Librem 5 ( USB2642 ) does not support UHS-I or UHS-II protocol and, so, will have lower speeds regardless of the speed rating of the card (you will get “Normal” or, at best, “High Speed” performance). See the quoted text in Why is internal card reader so slow? - #6 by Privacy2
There are different qualities of sdcards.
Speeds. You can read up on this, but there are official standards for sdcards in regard to speeds and various protocols. Note that this won’t do much for the Librem 5 … because the sdcard interface on the Librem 5 doesn’t support the protocol for higher speeds. See above.
Durability. Some sdcards are definitely built to deal with higher temperatures (e.g. cars for use in dashcams) and rougher environments (water resistant, shock resistant). I don’t think these ratings for durability are “official” (governed by uniform standards). Search on “extreme”, “extreme pro”, “high endurance”, “tough” … but the terminology depends on the brand (i.e. not official)
