peter@easthope.ca writes:
From: Linux-Fan <Ma_Sys.ma@web.de>
Date: Sat, 30 Jul 2022 21:37:37 +0200
> Formatting it to ext2 should work and not cause any issues ...
Other authorities claim "factory format" is optimal and wear of flash
storage is a concern. A revised "format" can impose worse conditions
for wear? Does any manufacturer publish about this? What is hope?
What is truth?
Reformatting (in the sense of mkfs.ext2) does not by itself cause excessive wear on the flash drive. Now if the cards were optimized to handle FAT and somehow interpret its structures cleverly then this could in theory cause longer life of the drives for FAT compared to ext2. So far we got some rumors about that but nothing definitive. I sincerely doubt that there are any advantages of FAT on SD beyond the compatibility. Because: Nowdays it is quite common to use these cards as general purpose storage. Encrypted storage of Android files come to mind. Here, the card cannot optimize beyond the block level which is what I guess it does in any case. Here are some resources that you could use for further research:
- https://www.reddit.com/r/raspberry_pi/comments/ex7dvo/quick_reminder_that_sd_cards_with_wearleveling/ - https://electronics.stackexchange.com/questions/27619/is-it-true-that-a-sd-mmc-card-does-wear-levelling-with-its-own-controllerI do not know of any case where an optimization for FAT became visible. Especially, having used SD and µSD cards for Linux root file systems for longer than a year without observing any issues, I would conclude that it is much more related to the quality of the flash than the file system in use.
> Modern backup tools use their own archive/data formats ... All that's needed here is a reliable copy on the HDD, of the files on the SD. If the SD fails I mount the part of the HDD, restore to another SD and continue working. Rsync is the most effective tool I've found. More advanced archiving is not needed.
rsync on FAT will not preserve Unix permissions and most other metadata. I (personally) would not consider it “reliable” since I care about these metadata.
There are three ways around this: * Don't care - If your workflow does not need any Unix permissions whatsoever then you might as well stick with FAT if none of its other limits are of concern (maximum file size for FAT32 comes to mind). * Format using an Unix-aware file system like e.g. ext2 and then just copy the files (rsync works). * Use a tool that keeps the metadata for you (like the suggested advanced backup tools). If rsync works for you, then by all means stick with it :) HTH Linux-Fan öö [...]
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